Ophthalmology
Explorer
1st Edition
Dhaval Patel
MD (AIIMS)
Ophthalmology Post-PG Examination Guide
Ophthalmology Explorer
Ophthalmology Post-PG Examination Guide
Dhaval Patel MD (AIIMS)
drdpatel87@gmail.com
by ophthalmologyexplorer.blogspot.com
1st edition, April 2014
This is a compilation effort from my preparation notes and other sources, thus
any contributions or comments are welcomed in the effort to improve this book.
Therefore, feel free to e-mail me at
drdpatel87@gmail.com
Ophthalmology Explorer
Dhaval Patel MD
PREFACE
The CLASS is knowing what to say, when to say and when to stop.
Dear Friends,
If you are reading this, then either you are approaching your final ophthalmology exams
or you are preparing for further study courses in ophthalmology.
So first thing I want you to know is the course for this exam include all aspects of
ophthalmology in different amounts and nobody knows it perfectly. This preparation manual I
have prepared during my residency and added up while preparing for senior residency/
fellowship examinations preparation which may serve as a small guide to your preparation. It
will also serve as a good collection of facts which we might forget/neglect during overall MD/MS
exam preparation.
So whatever it may serve you, I am proud of what I have prepared and I feel it worth
sharring with all emerging ophthalmologist friends.
All the Best..!!
-Dhaval Patel MD
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Ophthalmology Explorer
Dhaval Patel MD
INDEX
Exploring EYE .................................. 6
Basic Sciences ............................... 90
Optics & Refraction ......................... 122
Cornea........................................ 160
Lens ........................................... 192
Glaucoma .................................... 205
Retina ......................................... 226
Uvea .......................................... 264
Strabismus ................................... 275
Neurophthalmology ......................... 284
Oculoplasty .................................. 310
Community Ophthalmology................ 337
Miscellaneous ............................... 342
Lateral Thinking ............................. 356
The Class Questions ....................... 364
Important History ............................ 369
Recalls from previous papers ............. 370
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Ophthalmology Explorer
Dhaval Patel MD
Exploring EYE .................................. 6
Genes ....................................... 29
AAO Color Codes of Topical Medication: 6
Giant Cells .................................. 35
Age Related Changes ...................... 6
Growth Factors ............................ 35
Aquaporins ................................... 7
Half Life ..................................... 36
Acquisition time .............................. 7
HLA .......................................... 37
Axis and Angles ............................. 8
HLA wise Diseases ..................... 37
Bimodal Age Distribution ................... 8
Disease wise HLAs ..................... 37
Blocks ......................................... 9
Host Cell Receptors ....................... 38
Cell Cycle Phase Facts ..................... 9
Host for Parasites ......................... 39
Collagen Collection ....................... 10
Hypersensitivity in Eye .................... 39
Contents of Important Fluids ............ 11
IHC Markers ................................ 40
Chromosomes for Eye .................... 13
Inheritence .................................. 41
Connexins .................................. 19
Inside Retinal Layers ...................... 42
Craniosynostosis .......................... 20
Interferons Therapy & Eye ............... 43
Diameters .................................. 20
Intraocular Gases .......................... 44
Drug Resistance ........................... 21
Intracameral Dosages .................... 44
Dye for Eye................................. 21
Intrastromal Dosages ..................... 45
Electromagnetic Spectrum ............... 21
Intravitreal Dosages ....................... 45
Evolutions of anesthetic techniques for
cataract surgery ........................... 22
Intravitreal Implants ....................... 46
FDA Approved Drugs ..................... 23
FDA Device Classification ............... 26
Field of View ............................... 27
First in Genetics ........................... 27
Fellow Eye Risk ........................... 28
Frequency of Probes ..................... 29
Iris Nodules & Pathology ................. 48
Laser Facts ................................. 48
Brief History.............................. 48
Instrument Wavelengths ............... 49
Therapeutic Wavelengths ............. 49
Laser settings for glaucoma ........... 50
Laser settings in Retina ................ 51
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Ophthalmology Explorer
Dhaval Patel MD
Laser Parameters for PTK ............ 51
DME ...................................... 74
Modes of Laser ......................... 51
ROP....................................... 76
Laser Mediums ......................... 52
ARMD .................................... 77
Laser Safety Classification ............ 52
Vitreomacular interface (VMI) diseases
............................................ 81
Latest Drugs ............................... 53
Mechanism of Action ..................... 57
MIP .......................................... 58
MMPs ....................................... 58
Molecular Weights ........................ 59
MUCins ..................................... 59
NV % ........................................ 60
OCT Review ............................... 61
Optic Nerve Segments ................... 62
Orders of Abberations .................... 63
Percentages % Primer ................... 63
Phacomatosis .............................. 65
Principles ................................... 66
Radiation and Eye......................... 67
Rates ........................................ 67
Recurrence %.............................. 68
Refractive Indices ......................... 69
Resolutions................................. 70
RB Stats .................................... 71
Racial predilection of Diseases ......... 72
Studies and Trials ......................... 72
DR ........................................ 72
Glaucoma ................................ 82
ON ........................................ 83
NAION .................................... 83
MISC ...................................... 83
Surface Tension ........................... 84
Specific Gravity ............................ 84
Surface Area ............................... 85
Survival Rates.............................. 85
Test Distances ............................. 86
Thickness ................................... 87
VEGF Facts ................................ 88
Vitreous cavity volume displacement ... 89
Water Content.............................. 89
Basic Sciences ............................... 90
Optics & Refraction ........................ 122
Cornea ....................................... 160
Lens .......................................... 192
Glaucoma ................................... 205
Retina ........................................ 226
Uvea.......................................... 264
Strabismus .................................. 275
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Ophthalmology Explorer
Dhaval Patel MD
Neurophthalmology ......................... 284
Lateral Thinking ............................ 356
Oculoplasty .................................. 310
The Class Questions....................... 364
Community Ophthalmology ................ 337
Important History ........................... 369
Miscellaneous ............................... 342
Recalls from previous papers ............ 370
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Ophthalmology Explorer
Dhaval Patel MD
Exploring EYE
AAO Color Codes of Topical Medication:
Based on the American Academy of Ophthalmology recommendations to the FDA to aid
patients in distinguishing among drops and thus minimize the chance of using an incorrect
medication

Purple Cap: Alpha-Adrenergic Receptor Agonists

Yellow or Blue Cap: Beta-Blockers

Green Cap: Cholinergic Agonists, Miotics

Orange Cap: Carbonic Anhydrase Inhibitors

Turquoise/Teal Cap: Prostaglandin Analogues

Red Cap: Mydriatic/ cycloplegic agents

Tan Cap: Anti-infectives

Pink Cap: Steroids/ Anti-inflammatory

Gray Cap: Nonsteroidal anti-inflammatories

Dark Blue: beta-blocker combination
Age Related Changes

Ganglion cell loss: 5000/year

Endothelial cell loss: 0.6%/year

Decrease in ACD due to increase LT: 20 microns/year

Age related loss of VF sensitivity: 1 db/year

15.6-μm decrease in choroidal thickness for each decade of life

LENS thickness increases 0.2 mm per 10 year.
20 year: 3.8 mm
40 year: 4.4 mm
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Ophthalmology Explorer
Dhaval Patel MD
60 year: 4.8 mm
80 year: 5.2 mm

central anterior chamber depth decreases 0.01 mm/year
Aquaporins

Water channels are known as aquaporins and lens epithelial cells contain an abundance of
these.

MIP26 is believed to be a very old (and not very efficient) member of the aquaporin family
and is termed aquaporin O.

Types
o
AQP0 (MIP) in lens fiber
o
AQP1 in cornea endothelium, ciliary and lens epithelia and trabecular meshwork
o
AQP2 is not present in eye and is restricted to the kidney collecting duct
o
AQP3 in conjunctiva
o
AQP4 in ciliary epithelium and retinal Müller cells
o
AQP5 in corneal and lacrimal gland epithelia

AQP1 protects against vascular leakage by stabilizing the formed vessels.

NMO-IgG is a disease-specific autoantibody for neuromyelitis optica (NMO) and its target
antigen is aquaporin-4 (AQP4) water channel.
Acquisition time

Pentacam: 2 sec

OCT: 1 to 5 sec

Visante ASOCT: 3.3 sec
o
Anterior segment scan ( 16×6mm): 256 A-scan/ 0.125 sec
o
High resolution scan: 512 A-scan/ 0.25 sec
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Ophthalmology Explorer
o
Dhaval Patel MD
Pachymetry scan: 128 A-scans/0.5 sec

Dynamic light scattering DLS for lens pathology: 5 sec

CSLO: 1.6 sec
Axis and Angles
Axis of the Eye
FOVea
o
Fixation Axis: This is a straight line that joins center of rotation of eyeball with fixation point
o
Optical Axis: A line passing through center of cornea, center of lens and posterior pole of
retina is the optical axis of eyeball
o
Visual Axis: A line joining point of fixation with fovea and passing through nodal point of
eyeball is called visual axis. Nodal point of eyeball is just anterior to posterior capsule of lens.
Fixation point is the point which is being seen with fovea at any particular moment.
o
Pupillary Line: This is a straight line that passes through center of pupil
Angles of the Eye
o
Angle Alpha is the angle formed between optical axis and visual axis. AOV
o
Angle Kappa is the angle formed between visual axis and pupillary axis. KaVPa
o
Angle Gamma is the angle formed between optical axis and fixation axis. GOF
POsitive angle Kappa results in pseudoeXotropia. K-POX
Bimodal Age Distribution

Craniopharyngioma (peaking in the first 2 decades and again in the years 50 to 70

Thyroid orbitopathy (for women occur from ages 40 to 44 years and 60 to 64 years; for
men from ages 45 to 49 years and 65 to 69 years)

Hodgkin's lymphoma (early peak at 15 to 35 years of age and a second peak after 50)
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Ophthalmology Explorer

Glaucoma in SWS: (early-onset/congenital-type and later-onset)

Ocular Trauma
Dhaval Patel MD
Blocks
Facial Blocks: LOAN

van Lint‘s block: Blocking the peripheral branches of facial nerve

O‘Brien‘s block: Facial nerve trunk block at the neck of mandible

Atkinson‘s block: In it superior branches of the facial nerve are blocked by injecting
anaesthetic solution at the inferior margin of the zygomatic bone.

Nadbath block: facial nerve is blocked as it leaves the skull through the stylomastoid
foramen.
Other Blocks

Retrobulbar block was introduced by Herman Knapp in 1884

Peribulbar block was described in 1986 by Davis and Mandel
Cell Cycle Phase Facts

Thymocyte- T cells: G0 arrest

Stem Cells: G0 arrest

Endothelial Cells: G1 arrest

central zone epithelial cells of lens capsule: G0 arrest

In the G1 phase of the cell cycle, the RB-protein is hypophosphorylated.
In S, G2, and M, it is hyperphosphorylated.
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Ophthalmology Explorer
Dhaval Patel MD

p53 mediates arrest of the cell cycle in the G1 phase after sublethal DNA damage

Rb gene arrests cells in the G1 or G1/S-phase of the cell cycle, and stops further
proliferation.

Mitomycin C acts on all phases of cell cycle.
Collagen Collection

Type 1: corneal stroma, tarsal plate

Type 2: vitreous

Type 3: ciliary process

Type 4: Descemet membrane, lens capsule, PNBZ, basal lamina of corneal epithelium

Type 5: Bowman membrane

Type 7: ABZ

Cornea total Collagen 15%
o
o
fibrous collagens types I, II, III and V

Type I 50-55%

Type III ~ 1%

Type VI 25-30%
non-fibrous collagen type IV

Type IV 8-10%
o
filamentous collagens types VI, VIII, IX and X
o
basal lamina of the epithelium contains type IV collagen
o
Bowman‘s layer: type V
o
predominant collagen (about 90%) of the stroma is type I
o
Descemet's membrane contains predominantly type IV collagen, with about 10%
type V
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Ophthalmology Explorer
Dhaval Patel MD

BM of ciliary process and ciliary muscles ECM: laminin and collagen types I, III, and IV

human trabecular meshwork: collagen types I and III and elastin

Juxtacanalicular Tissue: collagen type III but no collagen type I or elastin

steroid-induced glaucoma shows increase in fine fibrillar material stains for collagen type
IV in the subendothelial region of the Schlemm canal

anterior uveitis: reducing the density of collagen type I in the extracellular matrix of the
ciliary body leading to increase in uveoscleral flow

lamina cribrosa of the human optic nerve head: collagen types I through VI, laminin, and
fibronectin

Topical prostaglandin F2alpha treatment reduces collagen types I, III, and IV in the
monkey uveoscleral outflow pathway
Contents of Important Fluids

BSS: Na, K, Ca, Mg, Cl, Citrate, Acetate
BSS plus: ―+ HCO3, PO4, Glucose, Glutathione
Aqueous: ―+ Lactate, Ascorbate, Protein

M.K. Media (4days): Tc199, Dextran, PH 7.0-7.5, Osmolality 295-355, gentamycin sulphate
75-150 micro gm/ml, HEPES as buffer, Phenol red as indicator

K-Sol: Tc 199, MEM & Earles media, HEPES, Gentamicin, Chondroin sulphate 2.5%

Dexol: MEM, 1.35% Chondrotin Sulphate, 1mM Sodium pyruvate, 1mM non- essential
amino acids, Antioxidants, 1% dextran40.

Optisol GS: MEM, 1.35% Chondrotin Sulphate, 1mM Sodium pyruvate, 1 mM non-essential
aminoacids, Antioxidants, 1% dextran40, ATP, Iron, cholestrol, L-hydroxyproline, Vitamins, 2
antibiotics- Gentamycin, Streptomycin

Procell: MEM,1.35%chondrotin sulphate,1mM sodium pyruvate1mM,Non-essential
aminoacids,Antioxidants,Dextran40, Humen insulin 10 ug/ml & Human epidermal growth
factor hEGF 10ng/ml to improve long term endothelial survival after PKP

Eusol-C: Store at 4 deg.C, Dextran, Sodium Piruvate, Glucose, Essential & non-essential
aminoacids, mineral salts, Vitamins, Gentamin, hepes buffer, Bicarbonate, Phenol Red
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Ophthalmology Explorer
Dhaval Patel MD

Organ culture medium: Fetal Bovine Serum, L-Glutamine, Earle's salts and 0.44%
Mercaptoethanol in addition to the other constituents present in most intermediate storage
media

Aqueous contents
Relative to plasma, aqueous humor has

o
Slight hypertonicity and acidity (pH 7.2 in AC)
o
Marked excess of ascorbate (15 times greater than arterial plasma)
o
Marked deficit of protein (0.02% in aqueous vs. 7% in plasma)
o
Only calcium and phosphorus are in concentrations of about one-half that in plasma.
o
Chloride and bicarbonate vary from 20% to 30% above or below plasma levels.
o
Sight excess of lactic acid
o
Slight deficit of sodium, bicarbonate, carbon dioxide, and glucose
o
Protein and antibodies in aqueous equilibrate with those in serum when a plasmoid
aqueous occurs with an anterior uveitis
o
Albumin/globulin ratio is similar to plasma, although there is less gamma globulin
Tear contents
o
Lipid layer

o
Wax, cholesterol, fatty acid esters
Aqueous layer

Water

electrolytes (Na+, K+ Cl–, HCO3–, Mg2+)

proteins (albumin, lysozyme, lactoferrin,transferrin, ceruloplasmin),

immunoglobulins (IgA, IgG, IgE, IgM)

cytokines

growth factors (EGF, TGF-α, TGF-β1, TGF-β2, bFGF, HGF, VEGF,
substance P)
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Ophthalmology Explorer

o
others (glucose, vitamins)
Mucinous layer

o
Dhaval Patel MD
Sulfomucin, cyalomucin, MUC1, MUC4, MUC5AC
IgD has not been detected in any study of human tears.
Chromosomes for Eye
Chromosome 1:

Fuch‘s dystrophy, COL8A2, AD

Posterior polymorphous dystrophy, PPCD2, AD

Stickler syndrome, COL2A, AD

Gelatinous drop like dystrophy, TYACSTD, AR

Schnyder corneal dystrophy, MJNFR, AD

EDS, EDS6, AR

Congenital glaucoma, GLC3B, AR

JOAG, Myocillin, AD

Stargardt‘s, ABCA4, AR

ARMD, CFH1

Usher syndrome, AR

Chediak higashi syndrome, LYST, AR

Leber‘s congenital amaurosis, RPE65, AR
Chromosome 2:

Congenital Glaucoma, CYP1B1, AR

Oguchi‘s disease, Arrestin, AR
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Ophthalmology Explorer

PXE, laminin/fibrillin, AR

Autosomal dominant drusen, EFEMP1, AD

Fleck dystrophy, PIP5K3, AD
Dhaval Patel MD
Chromosome 3:

BPES 1 (with premature ovarian failure) and BPES 2 (without premature ovarian failure) are
caused by type 1 mutations in FOXL2 gene

Von Hippel–Lindau syndrome Inheritance is AD condition caused by a mutation of the VHL
gene clusterin

Retinitis pigmentosa, Rhodopsin, AD

Xeroderma pigmentosa, NER enzyme, AR

Alkaptonuria, homogentisate 1-2 dihydroxygenase, AR

Kjer autosomal dominant optic atrophy, OPA1, AD
Chromosome 4:

Axenfield Rieger syndrome, PITX2, AD

CSNB, PDE6, AR

Wolfram syndrome, WFS1, AR

Hurler syndrome, alpha L iduronidase, AR

Bietti dystrophy, CYP4V2, AR

Fraser syndrome, FRAS1, AR
Chromosome 5:

Treacher Collins syndrome (mandibulofacial dysostosis) Inheritance is AD with high
penetrance and variable expressivity, although 60% of cases occur with no family history
and are thought to arise by de novo mutation. The gene involved is the ‗treacle‘ gene
TCOF1 on chromosome 5q.
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Ophthalmology Explorer
Dhaval Patel MD

Cri du chat syndrome (partial deletion of 5p)

Mutations in TGFB1 on chromosome 5 cause CDB1, CDB2, lattice type 1, lattice type 3A,
Avellino, and granular dystrophy. These are therefore allelic variants.
Chromosome 6:

Adult-onset macular vitelliform dystrophy is caused by mutation in the RDS gene on chrn
Dysromosome 6p, as well as the BEST1 gene in common with juvenile-onset Best
dystrophy.

VEGF

Pattern dystrophy, RDS/ peripherin, AD

Axennfeld reiger syndrome, FOXC1, AD
Chromosome 7:

Galactosemia classic, galactose 1 phosphate uridyl transaferase, AR

Pigment dispersion syndrome, AD
Chromosome 8:
Chromosome 9:

Lattice 2, gelsolin, AR

Nevoid BCC syndrome, PTCH, AD

Rilet Day syndrome, IKBKAP, AR
Chromosome 10:

Crouzon syndrome Inheritance is usually AD, but 25% of cases represent a fresh mutation.
The gene (FGFR2) has been isolated to chromosome 10.

Thiel behnke dystrophy, AD
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Ophthalmology Explorer

MEN2B, RET proto-oncogene, AD

Gyrate atrophy, OAT, AR

NTG-COAG, optineurin, AD
Dhaval Patel MD
Chromosome 11:

Aniridia, peter‘s, AD keratitis, Axenfed reiger: PAX6, AD

Nanophthalmos, NNO1, AD

Best disease, 11q13 bestrophin, AD

FEVR, frizzled 4 gene, AD

OCA, TYR/OCA2, AR

CFEOM2: 11q13
Chromosome 12:

CFEOM-1:

Cornea plana, KERA, AR

CHSD, DCN, AD

Meesman dystrophy, KRT3, AD

Fundus albipunctatous, RDH5, AR
Chromosome 13:

Retinoblastoma, 13q14, AD

Sclerocornea, HCCS, AD

Microphthalmos, Trisomy 13

Congenital microcornea, AD

Oguchi disease, rhodopsin kinase, AR
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Ophthalmology Explorer

Late onset fuchs dystrophy, FECD2, AD

CFEOM-3
Dhaval Patel MD
Chromosome 14:

Oculopharyngeal dystrophy Inheritance is AD caused by mutation on chromosome 14q.
Chromosome 15:

Marfan syndrome: FBN1, AD
Chromosome 16:

Posterior Polar Cataract: mutation of PITX3 gene

Macular dystrophy, CHST6, AR

Pseudo xantoma elasticum, ABCC6, AR

Fish eye disease, LCAT, AR

Tyrosenemia, tyrosine amino transferase, AR
Chromosome 17:

Meesman dystrophy, AD

NF1, NF1, AD

Cystinosis, CTNS, AR
Chromosome 18:

Edwards syndrome (trisomy 18)

Transthyretin
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Ophthalmology Explorer
Dhaval Patel MD
Chromosome 19:
Chromosome 20:

CHED AD, CHED1 20911, AD

CHED AR< CHED2 20p13, AR

PPMD2, VSX1, AD
Chromosome 21:

Down syndrome (trisomy 21)

Homocystinuria: Inheritance is AR with the gene locus on chromosome 21q.22.3.
Chromosome 22:

NF2, NF2, AD

Sorsby dystrophy, TIMP3, 22q13, AD
Chromosome X:
XR

Fabry disease, alpha galactokinase

CSNB, calcium channels

Megalocornea, LTBP2

Coat‘s disease, NDP

FEVR, NDP

Retinitis pigmentosa, RPGR

Choroderemia, REP1

Norrie disease, NDP gene on chromosome Xp11.
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Ophthalmology Explorer
Dhaval Patel MD
XD

Lowe syndrome, OCRL1

Alport‘s syndrome, COL4A3

Aicardi syndrome

Incontinentia pigmenti: NEMO gene on chromosome Xq28.

Ichthyosis, STS
Chromosome Y:
Connexins

At electrical synapses a cytoplasmic bridge is formed by specialized proteins called
connexins. Six connexins form a hexagonal tube that projects out of the plane of the
plasma membrane of one participating cell; this unit is called a connexon.

Connexin 43:

o
gap junctions of lateral membranes of lens epithelial cells
o
oculodentodigital syndrome
Connexin 46 and 50:
o
Transmembrane proteins forming lens fiber gap junction is typically 16 nm thick
o
connexin 50 or MP70 is most prevalent in outer cortical fibers, where it undergoes
age-related degradation to MP38, which continues in functional gap junctions.

connexin mutations can give rise to congenital cataracts

Connexin 50, connexin 37, and connexin 40 are all encoded by genes consisting of a single
exon on chromosome 1q21

A zonular pulverulent cataract has been localized to chromosome 13 near the connexin
46 gene.
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Ophthalmology Explorer
Dhaval Patel MD
Craniosynostosis
SPOT:
Scaphocephaly: sagittal suture closure (aka 'dolichocephaly')
Plagiocephaly: unilateral Coronal suture (anterior) or Lamboid (posterior)
Oxycephaly: coronal suture plus any other suture, like the lambdoid
Trigonocephaly: metopic suture closure
Syndromes
Apert syndrome
Crouzon syndrome
Pfeiffer syndrome
Saethre-Chotzen syndrome
Diameters

Collagen fibres in corneal stroma: 25 nm diameter, 60 nm spacing between each pair

Collagen fibres in vitreous: 10 nm diameter

Lens fibre diameter: 10.5 um

Zonular fibres: 70-80 nm diameter, grouped into bundles of 5-50 um diameter

Cone diameter: 2 um with 0.3 um spacing

Cochet and Bonnet esthesiometer wire: 0.12 mm
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Ophthalmology Explorer
Dhaval Patel MD
Drug Resistance

CMV UL97 mutations (a CMV DNA polymerase mutation that confers ganciclovir
resistance) were detected in 3% of patients treated with ganciclovir over 3 months and in
none treated less than 3 months.
Dye for Eye


Anterior Segment (Capsule staining)
o
0.5% indocyanine green
o
0.15% trypan blue (less costly when compared to the cost of ICG)
Posterior Segment
o
ICG: ILM staining  0.05%
o
IFCG: 0.05%
o
TB: ERM stain  0.06%
o
BBG: ILM staining  0.05%, 0.025%
o
TA
o
PB
o
BrB
o
NaF
Electromagnetic Spectrum
(part of spectrum which is important in ophthalmology)
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Ophthalmology Explorer
Dhaval Patel MD

Ultraviolet C rays: This band is blocked by the ozone layer of atmosphere.

Ultraviolet B rays: This band is responsible for snow blindness and photo keratitis caused
by welding arc. Prolonged exposure to these rays can cause formation of pingicula and
pterigium.

Ultraviolet A rays: This band of UV rays is absorbed by crystalline lens and thus retina is
protected against their bad effects. Prolonged exposure to these rays causes cataract
formation. IOLs implanted during cataract surgery have chromophores [inhibitors of UV rays]
to protect retina against UV rays.

Visible Rays: VIBGYOR

Infrared A rays are responsible for macular burn in solar eclipse [photo retinitis].

Infrared rays B and C can cause corneal opacity and cataract formation on prolonged
exposure.
Evolutions of anesthetic techniques for cataract surgery

General anesthesia 1846

Topical cocaine 1881 Koller

Injectable retrobulbar cocaine 1884 Knapp

OrbicuIaris akinesia 1914 Van lint, O'Briens Atkinson

Hyaluronidase 1948 Atkinson

Peribulbar 1970 kelman (but not published)

Posterior peribulbar 1985 Davis and Mandel

limbal 1990 Furata et al.

Anterior peribulbar 1991 Bloomberg

Pinpoint anesthesia 1992 Fukasawa and Furata

Topical tetracaine 1992 Fichman

Topical plus intracameral 1995 Gills

No anesthesia 1998 Agarwal
22
Ophthalmology Explorer

Cryoanalgesia 1999 Gutierrez-Carmona

Xylocaine jelly 1999 Koch and Assia

Hypothesis, no anesthesia 2001 Pandey and Agarwal

Viscoanesthesia 2001 Werner, Pandey, Apple et al
Dhaval Patel MD
FDA Approved Drugs
Drugs Approved in 2012

Cystaran (cysteamine hydrochloride); Sigma Tau Pharmaceuticals; For the treatment of
corneal cystine crystal accumulation due to cystinosis, Approved October 2012

Jetrea (ocriplasmin); Thrombogenics; For the treatment of symptomatic vitreomacular
adhesion, Approved October 2012

Lucentis (ranibizumab injection); Genentech; For the treatment of diabetic macular edema,
Approved August 2012

Zioptan (tafluprost ophthalmic solution); Merck; For the treatment of elevated intraocular
pressure, Approved February 2012
Drugs Approved in 2011

Eylea (aflibercept); Regeneron Pharmaceuticals; For the treatment of neovascular (wet)
age-related macular degeneration, Approved November 2011
Drugs Approved in 2010

Zymaxid (gatifloxacin ophthalmic solution); Allergan; For the treatment of bacterial
conjunctivitis, Approved May 2010
Drugs Approved in 2009

Acuvail (ketorolac tromethamine); Allergan; For the treatment of pain and inflammation
following cataract surgery., Approved July 2009

Bepreve (bepotastine besilate ophthalmic solution); Ista Pharmaceuticals; For the treatment
of itching associated with allergic conjunctivitis, Approved September 2009

Besivance (besifloxacin 0.6% ophthalmic suspension); Bausch & Lomb; For the treatment
of bacterial conjunctivitis, Approved June 2009
23
Ophthalmology Explorer
Dhaval Patel MD

Ozurdex (dexamethasone); Allergan; For the treatment of macular edema following branch
retinal vein occlusion or central retinal vein occlusion, Approved June 2009

Zirgan (ganciclovir ophthalmic gel); Sirion Therapeutics; For the treatment of acute herpetic
keratitis, Approved September 2009
Drugs Approved in 2008

Akten (lidocaine hydrochloride); Akorn; For anesthesia during ophthalmologic procedures,
Approved October 2008

Astepro (azelastine hydrochloride nasal spray); Meda Pharmaceuticals Inc.; For the
treatment of seasonal and perennial allergic rhinitis, Approved October 2008

Durezol (difluprednate); Sirion Therapeutics; For the treatment of inflammation and pain
associated with ocular surgery, Approved June 2008
Drugs Approved in 2007

AzaSite (azithromycin); InSite Vision; For the treatment of bacterial conjunctivitis, Approved
April 2007
Drugs Approved in 2006

Lucentis (ranibizumab); Genentech; For the treatment of neovascular (wet) age related
macular degeneration, Approved June 2006
Drugs Approved in 2004

Macugen (pegaptanib); Pfizer / Eyetech Pharmaceuticals; For the treatment of wet agerelated macular degeneration., Approved December 2004
Drugs Approved in 2002

Restasis (cyclosporine ophthalmic emulsion); Allergan; For the treatment of low tear
production., December 2002
Drugs Approved in 2001

Lumigan (bimatoprost ophthalmic solution); Allergan; For the reduction of intraocular
pressure in patients with open-angle glaucoma or ocular hypertension, Approved March
2001

Travatan (travoprost ophthalmic solution); Alcon; For the reduction of elevated intraocular
pressure in patients with open-angle glaucoma or ocular hypertension, Approved March
2001
24
Ophthalmology Explorer

Dhaval Patel MD
Valcyte (valganciclovir HCl); Roche; For the treatment of cytomegalovirus retinitis in patients
with AIDS, Approved March 2001
Drugs Approved in 2000

Betaxon; Alcon; For lowering IOP in patients with chronic open-angle glaucoma or ocular
hypertension, Approved February 2000

Quixin (levofloxacin); Santen; For treatment of bacterial conjunctivitis, Approved August
2000

Rescula (unoprostone isopropyl ophthalmic solution) 0.15%; Ciba Vision; For the
treatment of open-angle glaucoma or ocular hypertension, Approved August 2000

Visudyne (verteporfin for injection); QLT; For the treatment of wet age-related macular
degeneration (wet AMD), Approved April 2000
Drugs Approved in 1999

Alamast; Santen; pemirolast potassium ophthalmic solution, Approved September 1999

ZADITOR; Ciba Vision; Treatment for the prevention of itching of the eye, Approved July
1999
Drugs Approved in 1998

Alrex; Bausch & Lomb, Pharmos; Treatment for seasonal allergic conjunctivitis, Approved
March 1998

Cosopt; Merck; Treatment for glaucoma or ocular hypertension, Approved April 1998

Lotemax; Bausch & Lomb, Pharmos; Treatment for post-operative eye inflammation,
Approved March 1998

Salagen Tablets; MGI Pharma; Treatment for Sjogren's Syndrome, Approved February 1998

Viroptic; King Pharmaceuticals; Treatment for inflammation of the cornea in children due to
herpes simplex virus, Approved February 1998

Vitravene Injection; Isis Pharmaceuticals; Treatment for CMV in AIDS patients, Approved
August 1998
Drugs Approved in 1997

Acular (ketorolac tromethamine ophthalmic solution) 0.5%; Allergan; Treatment for
postoperative inflammation in patients who have undergone cataract extraction, Approved
January 1997
25
Ophthalmology Explorer
Dhaval Patel MD

Acular (ketorolac tromethamine ophthalmic solution) 0.5%; Allergan; Treatment for postsurgical inflammation following cataract extraction, Approved November 1997

BSS Sterile Irrigating Solution; Alcon; Treatment during ocular surgical procedures,
Approved December 1997
Drugs Approved in 1996

AK-Con-A (naphazoline ophthalmic); Akorn; Over-the-counter combination
vasoconstrictor/antihistamine product for opthalmic use, Approved January 1996

Alphagan (brimonidine); Allergan; Treatment for open-angle glaucoma and ocular
hypertension, Approved September 1996

Ocuflox (ofloxacin opthalmic solution) 0.3%; Allergan; Treatment for corneal ulcers,
Approved May 1996

OcuHist; Pfizer; Over-the-counter antihistamine eye drop, Approved January 1996

Vistide (cidofovir); Gilead; Treatment for cytomegalovirus (CMV) retinitis, Approved June
1996

Vitrasert Implant; Chiron; Drug delivery system for the treatment of cytomegalovirus,
Approved March 1996
FDA Device Classification
3 classes of ophthalmology devices
1. Class I devices (eg, refractometers, perimeters, sunglasses, visual acuity charts) are
usually considered minimal-risk devices. Although these devices are subject to general
controls, most of them are exempt from premarket review by the FDA. With few exceptions,
manufacturers can go directly to market with a class I device.
2. Class II devices (eg, phacoemulsification units, tonometers, vitrectomy machines, dailywear contact lenses) are usually considered moderate-risk devices. Class II devices are
those for which general controls alone are insufficient to ensure safety and effectiveness
and for which methods exist to provide such assurances. These devices, in addition to
general controls, are subject to special controls, which may include special labeling
requirements) mandatory performance standards, and postmarket su rveillance. With few
exceptions, class II devices requi re premarket review by the FDA.
26
Ophthalmology Explorer
Dhaval Patel MD
3. Class III devices (eg, excimer lasers, intraocular lenses, extended -wear contact lenses,
intraocular fl uids) are considered significant-risk devices that present a potential
unreasonable risk of illness or injury. Class III devices are those for which insufficient
information exists to ensure safety and effectiveness solely through general or special
controls. Class III devices cannot be marketed in the United States until the FDA
determines that there is a reasonable assurance of safety and effectiveness when used
accordi ng to the approved indications for use. Most class III devices come to market
through the premarket approval (PMA) process and require an extensive review by the FDA
before approval is granted for marketing.
Field of View

Standard Fundus Camera: 20, 30 and 50 degrees

RetCam: 130 degrees

Optos: 200 degrees of retina (equator is at 180 degrees)

First in Genetics
Wow…!! It’s amazing that all of following diseases first described in each category has an eye
manifestation…!!! (Ref: Alex Levin MD, WEI, PA, USA)
1st AD: Piebaldism
1st AR: alkaptonuria
1st XR: red green colour deficiency
1st XD: Incontigenta pigmenti
1st Mitochondrial: LHON
1st digenic: RP
1st trigenic: bardet biedel
27
Ophthalmology Explorer
Dhaval Patel MD
1st two-hit hypothesis: Retinoblastoma
1st contiguous gene deletion syndrome: anridia syndrome of wagner
Fellow Eye Risk

Keratoconus: 50% of normal fellow eyes will progress to keratoconus within 16 years

PXG: A patient with unilateral PXG and only PXF in the fellow eye is at high risk (50% in 5
years) of developing glaucoma in the fellow eye. A patient with unilateral PXG who does not
have PXF in the fellow eye has only a low risk of developing glaucoma in the normal eye.

Patients with advanced AMD (late ARM) in one eye, or even moderate vision loss due to
non-advanced AMD in one eye, have about a 50% chance of developing advanced AMD in
the fellow eye within 5 years.

In Age related Macular Hole, risk of involvement of the fellow eye at 5 years is around 10%.

In NAION, Involvement of the fellow eye occurs in about 10% of patients after 2 years and
15% after 5 years.

AAION affects 30–50% of untreated patients of which one-third develop involvement of the
fellow eye, usually within 1 week of the first.

7% of patients with CRVO develop a nonsimultaneous venous occlusion of the fellow eye
within 2 years

The risk of any vascular occlusion in the fellow eye is estimated to be 0.9% per year.

The Macular Photocoagulation Study (MPS) reported that the 5-year risk of
neovascularization in fellow eyes of individuals with unilateral neovascular AMD was 10%
in those without large drusen and 30–46% in those with large drusen

POHS with CNVM, 20% risk over a 2-3-year period of developing choroidal
neovascularization in the macula of the fellow eye

50-75% of patients with angle closure in one eye will have an attack in the fellow eye
often within 1 year (up to 10years) despite miotic treatment. Prophylactic laser iridotomy in
fellow eyes of patients presenting with unilateral acute PAC also appears to be safe and
effective in preventing acute PAC in 100%, and in preventing long-term rise in IOP in 89%
28
Ophthalmology Explorer
Dhaval Patel MD

Acute retinal necrosis may occur in the fellow eye in approximately 30% of patients at an
average interval of 4 weeks.

Chances of RD in fellow eye varies from 9-40%.
Frequency of Probes

USG: 10 MHz

Ultrasonic Pachymetry: 10-20 MHz

UBM: 50 MHz

HI-SCAN: 35 MHz
Genes

Genotypic heterogeneity: multiple genes causing single disease

Phenotypic heterogeneity: single gene causing multiple disease

PXF: LOX L1

BPES: FOX L2

Pterygium: KL-6

Lowe‘s syndrome: OCRL1 gene

TGFB1: aka BIGH3
o
5q31.2
o
Protein produced by corneal epithelium
o
Phenotypic heterogeneity
GREAT

Granular

Reis Buckler
29
Ophthalmology Explorer



EBMD

lAttice

Thiel Behnke
Dhaval Patel MD
PAX6, 11p13: phenotypic heterogeneity
o
Aniridia
o
Gillespe
o
WAGR
Axenfield Reiger Spectrum (AD) – genotypic heterogeneity, multiple genes causing same
disease
o
GJA1 (connexin 43)  6p21
o
FKHL7/ FOXC1  6p25
o
PITX2/ RIEG1 4q25
o
RIEG2  13q14
o
COL4A1  13q34
(MCQ: all except type question, so remember its Chromosomes 4, 6 and 13)

Fuchs: genetic heterogeneity
o
Following all genes do cause Fuchs and other diseases mentioned below.

COL8A2: PPMD

SLC4A11: CHED

ZEB1: PPMD

PITX2: homeobox gene  Peters, ARS, AN, Iris hypoplasia

KCNJ13: upregulates ZEB1
30
Ophthalmology Explorer

Dhaval Patel MD
Keratin genes: cytokeratin 12 + 3
o
KRT3: 12q13  Meesman
o
KRT12: 17q12  Stocker Holt

Keratoconus: VSX1, SOD1

Glaucoma Genes nosology:
o
GLC is name given to primary gene loci by HUGO: Human Genome
Organisation, Geneva
o
GLC1: open angle (only 10% pt): AD

Only 3 genes are known till now

GLC1A: JOAG 36%, POAG 4%  1q23-25  MYOC/TIGR

GLC1B: POAG  2q  nI IOP

GLC1C: POAG 3q  high IOP

GLC1D: POAG  8q23  high IOP

GLC1E: POAG/NTG 16%  10p14  Optineurin (OPTIc NEURopathy
INducing), nI IOP

GLC1F: POAG  7q

GLC1G: POAG 5%  5q  WDR36 (WD Region 36)
o
GLC2: close angle
o
GLC3: congenital (>25%): AR
o

GLC3A: 2p21  CYP1B1, cyrochrome P450 gene

GLC3B: 1p36

GLC3C: 14q24

MYOC is responsible for 5.5% PCG
Pigment Dispersion Genes: AD, 7q35
31
Ophthalmology Explorer
o
Pseudoexfoliation syndrome: LOXL1, 15q24-25
o
Genes associated with MMP
o
o

Dhaval Patel MD

MMP9 downregulated during acute PACG

SNP rs17576 of MMP9 at chromosome 20q11 is strongly associated with
acure PACG.
Genes Causing Early-Onset or Familial Glaucoma

CYP1B1, Cytochrome p450  Congenital glaucoma

LTBP2, Latent transforming growth factor beta binding protein 2 
Congenital glaucoma

PITX2, Paired-like homeodomain 2  Axenfeld-Riegers

FOXC1, Forkhead box C1  Anterior segment dysgenesis

PAX6, Paired box 6  Aniridia

MYOC, Myocilin  Primary open-angle glaucoma (juvenile and familial)

OPTN, Optineurin Familial normal-tension glaucoma

TBK1, TANK-binding kinase 1  Familial normal-tension glaucoma

LMX1B (9q34, glaucoma associated with nail-patella syndrome)
Glaucoma Gene Testing

Congenital glaucoma  CYP1B1, LTBP2

Anterior segment dysgenesis  FOXC1, PITX2, PAX6

Primary open-angle glaucoma  MYOC

Normal-tension glaucoma  OPTN, TBK1, OPA1
Eyelid Tumors genes
o
o
BCC:

Sonic hedgehog pathway

PTCH1 (patched 1): in BCNS or Gorlin syndrome
SeCA:
32
Ophthalmology Explorer

o
Muir Torre Syndrome

MMR- Mismatch Repair genes (MSH-2, MSH-6, MLH-1)

MSI- high frequency of Micro Satelite Imbalance
Merkel Cell Carcinoma

MCPyV: Merkel Cell Polyoma Virus  70% cases

o


Dhaval Patel MD
LTA: Large T Antigen binds to host proteins, forces cell into Sphase
Cutaneous Malignant Melanoma

C-KIT activating mutations  chronic sun damage MM (Acral MM, Mucosal
MM)

BRAF activating mutations V600E (90%)  Non chronic sun damage MM
 Nevi

P16INK4a-Rb pathway: loss of function mutation of CDKN2A  Familial
melanoma (dysplastic nevus syndrome)

Melanocortin receptor (MC1R) varients  increased risk of MM and BCC
independent of cutaneous pigmentation
ARMD
o
Complement factor H gene (CFH): 1q32
o
Apolipoprotein E: 19q13.2
o
Many others..BIG BIG list!!
Retinal/Macular Dystrophies
o
Best macular dystrophy
o
Stargardt disease ABCA4, Chr 1
o
Stargardt-like dominant macular dystrophy
o
Pattern dystrophy PRPH2
o
Sorsby fundus dystrophy TIMP3 Chr 22 AD
BEST1,
Chr11 AD/AR
AR
ELOVL4 Chr 6 AD
Chr 6 AD
33
Ophthalmology Explorer

Dhaval Patel MD
o
Autosomal dominant radial drusen
EFEMP1
Chr 2 AD
o
North Carolina macular dystrophy
Unknown
Chr 5 and 6
o
Spotted cystic dystrophy Unknown
Unknown
AD
o
Dominant cystoid macular edema
Unknown
Chr 7 AD
o
Fenestrated sheen macular dystrophy
Unknown
Unknown
o
Glomerulonephritis type II CFH
AD
AD
Chr 1 AR
Mutations of LHON
o
11778: 98% patients, VA < 20/200, worst prognosis
o
14484: 10-15% patients, high incidence of spontaneous VA recovery, best prognosis
o
3460: 8-15% of patients, high incidence of visual recovery, family history positive

Gene therapy: for LCA, RPE 65 gene, NEJM 2008 study, Lancet 2009

Ocular development genes:
o
Sonic hedgehog
o
Paired box
o

PAX2: (during optic vescicle, causes ocular-renal coloboma syndrome)

PAX6 (eye development)
Other downstream genes  CHX10, FKHL7 (6p15, forkhead transcription factor, ?
neural crest), PITX2

Genes causing Diabetes: ALR2, RHGE, TGF beta1

Uveal melanoma gene: DDEF1 gene, chromosome 8q

The ATP-binding cassette
o
Subfamily A:ABCA

Adrenoleukodystrophy
34
Ophthalmology Explorer
o

Zellweger syndrome

Stargardt disease (ABCA4)

Autosomal recessive retinitis pigmentosa

Cone-rod dystrophy
Dhaval Patel MD
Subfamily G: ABCG

ABCG2: limbal stem cells

Giant Cells

Langhans giant cells: peripheral ring of nuclei, associated with tuberculosis, sarcoidosis

Touton giant cells: midperipheral ring of nuclei surrounded by a peripheral ring of lipid,
associated with xanthogranulomatous disease

Foreign body giant cells: randomly dispersed nuclei, associated with foreign material and
fungi
Growth Factors

INF-Y: decreases angiogenesis

PEGF: decreases neovascularisation

Angiopoeitin: decreases leakage
o
Angiopoietins-1–4 (Ang1–4) form a family of growth factors involved in angiogenesis
o
only Ang1 and Ang2 currently are known to have roles in ocular neovascular disease
o
Endothelial cells are a primary source of Ang2 production where it is stored in
Weibel–Palade bodies (WPB) from which it can be released by a variety of stimuli

Myofibroblasts are derived from keratocytes under influence of TGF beta1.

HGF and KGF are predictor of corneal epithelial healing.

Keratocytes apoptosis is mediated by IL-1.
35
Ophthalmology Explorer
Dhaval Patel MD

PKC beta is most important in DR pathogenesis. It increases basement membrane
permeability.

Angiogenesis is regulated by a balance between VEGF and PEDF (pigment endothelium
derived factor), as evidence is emerging that PEDF may inhibit new blood vessel growth.

PDGF-B is a growth factor structurally related to VEGF. The contributions of PDGF-B to
angiogenesis are mediated largely through its effects on mural cells such as pericytes and
vascular smooth muscle cells.

Half Life




IVTA
o
Normal eye: 41 days
o
Vitrectomised eye: 16 days
o
Aphakic eye: 6.5 days
PST
o
Aqueous: 11 days
o
Vitreous: 17 days
o
Plasma: 25 days
Intravitreal Bevacizumab 1.25mg
o
4.32 days rabbit
o
5 days in humans
Intravitreal Ranibizumab 0.5 mg
o

3 days in monkeys
Strontium-90: 28 years
36
Ophthalmology Explorer
Dhaval Patel MD
HLA
HLA wise Diseases

A2: JIA

A11: Sympathetic ophthalmia

A29: birdshot chorioretinopathy (90-100% association)

B5, B12: behcet's dz

B7: toxoplasmosis, POHS, serpiginous choroidopathy, ankylosing spondylitis, APMPPE

B8: Sjögren‘s syndrome, sarcoidosis

B12: Ocular cicatricial pemphigoid

B13: sarcoidosis

B27: PAIR  Ankylosing spondylitis (88%), Reiter‘s syndrome (85–95%), inflammatory
bowel disease (60%), psoriatic arthritis (also B17).

B51: behcet‘s disease, eales

Bw54: Posner-Schlossman syndrome, VKH?

DR2: POHS, intermediate uveitis, APMPPE

DR4: VKH, SO, OCP.

DR2/15: pars planitis and Multiple Sclerosis
Disease wise HLAs

Keratoconus: A9/10/12, B5/21

PXF: A1/33, B8

OHT progression to Glaucoma: B7/12

AMD: A3, CW02/07

Diabetic Retinopathy (DR) development: DR1/7

Diabetic Retinopathy (DR) proliferation: DR4, DQ8
37
Ophthalmology Explorer
Dhaval Patel MD

Retinal vasculitis: B44

Eales: B51, DR1/4

IU: B8/51, DR2

Pars Planitis: DR15/17/51

VKH: HLA-DR4 and HLA-Dw53 are more common in Chinese patients, HLA-DR1 and HLA
DR4 more common in Hispanic patients, and HLA DRB1 in Indian patients

SJS: significantly increased incidence of HLA-B12, HLA-Aw33, and DRw53

HSV EM: HLA-DQw3

TEN: HLA-B12

ocular lesions of SJS: HLA-B44

Birdshot choroidopathy: White, HLA-A29, 96%

Ankylosing spondylitis: White and asians, HLA-B27, 89%

Behçet's disease: Japanese, HLA-B5, 68%

Reiter's syndrome: White, HLA-B27, 80%

POHS: White, HLA-B7-77%, HLA-DR2-81%
Host Cell Receptors

Adenovirus type 37: CD46

Epstein–Barr virus: CD21

Herpes simplex virus: Heparan sulfate

Human cytomegalovirus: Heparan sulfate

Human papillomavirus: Integrin a6

Influenza virus: Sialic acid

Rhinovirus: ICAM-1

Vaccinia virus: EGF receptor
38
Ophthalmology Explorer
Dhaval Patel MD
Host for Parasites



Definitive:
o
Toxoplasma gondii: domestic and wild cats
o
Echinococcus granulosus: dog
o
Taenia solium: human
Intermediate host
o
Taenia solium: pig
o
Toxoplasma gondii: animals including humans
o
Echinococcus granulosus: sheep, cattles, pigs
o
Francisella tularensis: rabbit, squirrels, cats, foxes, raccoons
o
Brucellosis: veterinarians and abattoir workers
o
Oncocerca volvulus: many species of black fly simulium
Both definitive and intermediate:
o
Taenia solium: human
Hypersensitivity in Eye
Gell, Coombs, and Lackmann‘s classification of Hypersensitivity Reactions
o
Type 1: VKC, AKC, SAC, GPC
o
Type 2: OCP, PV, DH
o
Type 3: SJS, RA, SLE, PAN, RP
o
Type 4: TB, WG, Contact dermatitis, herpes disciform keratitis, sarcoidosis, transplant
rejection
39
Ophthalmology Explorer
Dhaval Patel MD
IHC Markers

Melanoma markers: HMB45, melan A, tyrosinase, S-100 , MITF

Epithelial markers: Cytokeratins (CAM 5.2, AE1, AE3, CK7, CK20, involucrin, etc.)

Endothelial markers: Factor VIII, CD34

Muscle markers: Muscle specific actin (MSA), smooth muscle action (SMA), desmin,
myogenin

Neuroendocrine tumors: Chromogranin

Melanoma: HMB45, S100

Neural tumor: S100, Leu7

Fibrous histiocytoma: CD68

Spindle cell carcinoma: Cytokeratin

Rhabdomyosarcoma: Desmin, Vimentin, Muscle specific actin, Myoglobin, Myogenin,
MyoD1, Caveolin-3

lymphoid tumors
o
CD3: T cells
o
CD5: T cells, mantle cells, SLL/CLL
o
CD10: follicular lymphoma
o
CD20: B cells
o
CD23: follicular dendritic cells
o
Bcl-2: follicular, anti-apoptosis
o
Bcl-1: cyclin D1, mantle cell

Retinoblastoma is positive for neuron-specific enolase (also found in aqueous of RB), class
III tubulin isotype (h4), microtubuleassociated protein 2 (MAP2), and synaptophysin; they
are negative for glial fibrillary acidic protein and S-100 protein

Retinal stem cell marker: nestin, CD 34

Mitosis specific marker in cornea: Ki67
40
Ophthalmology Explorer
Dhaval Patel MD

Limbus Stem Cells: CK 5/14+ve, CK 19+ve, P63+ve, Vimentin+ve, ABCG2, alpha-enolase
(5+14 =19)

Central Corneal Cells: CK 3/12+ve, Connexin 43+ve (3 x 4 = 12, 4.3)


Inheritence

All vitreoretinopathy are AD except
o
Norrie  XL
o
XLRS  XL
o
Glodman favre  AR
o
Stickler  AD but rarely AR
o
FEVR  AD AR XR

All MPSs are transmitted by the AR mode, except MPS II (Hunter syndrome) which is
XR.

albinism inheritance

o
All OCA are AR except ADOCA
o
OA are XR.
All corneal dystrophies are AD except
o
Macular  AR
o
Gelatinous droplike  AR
o
LCD type 3  AR
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Ophthalmology Explorer
o

Dhaval Patel MD
CHED type 2  AR
Microcornea: AD
Megalocornea: XR

Familial ectopia lentis is AD
Ectopia lentis et pupillae is AR.

Simple myopia and simple hypermetropia: AD
Inside Retinal Layers

The nuclei of the Müller cells lie in the inner nuclear layer, whereas the nuclei of the
photoreceptors lie in the outer nuclear layer.

The nerve fiber layer contains the axons of the ganglion cells.

The inner plexiform layer has axons of the bipolar and amacrine cells and the synapses
of the ganglion cells.

The outer plexiform layer has connections between the photoreceptors, horizontal cells,
and bipolar cells.

The footplates of the Müller cells form the internal limiting membrane.

cell bodies whose processes project into the lateral geniculate and pretectal nuclei
ganglion cell layer

Müller's cell nuclei  inner nuclear layer

Photoreceptors nuclei  Outer nuclear layer

horizontal and bipolar synapses  outer plexiform layer

amacrine and bipolar cell synapses  inner plexiform layer

storage of dietary vitamin A  retinal pigment epithelium (RPE)

cell bodies whose processes form spherules and pedicles  outer nuclear layer
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Ophthalmology Explorer
Dhaval Patel MD

high baseline cyclic guanosine monophosphate (cGMP) levels and membrane
depolarization  photoreceptor layer

flame-shaped retinal hemorrhages  nerve fiber layer

dot hemorrhages  inner nuclear layer

Hard exudates  OPL

Soft exudates/ CWS  NFL
Interferons Therapy & Eye

Alpha 2a: capillary hemangioma

Alpha 2b: papilloma

Beta 1a:

o
Avonex: for MS, intramuscular, once weekly
o
Rebif: for MS, subcutaneous, thrice weekly, EVIDENCE Trial
Beta 1b:
o

Betaseron and Extavia: for MS, subcutaneous
Gamma
o
chronic granulomatous disease, kidney tumors and leishmania and other parasites.
43
Ophthalmology Explorer
Dhaval Patel MD
Intraocular Gases
Physical characteristics
Gases
Mol wt.
Purity
(mole%)
Expansion
Longevity
(days)
Nonexpansile
conc. (%)
Air
29
99.99
0
5-7
----
SF6
146
99.9
1.9-2.0 times
10-14
18
C3F8
188
99.7
4 times
55-65
14
Intracameral Dosages

Vancomycin: 1 mg/ml

Cefazolin: 1 mg/0.1 ml

Cefuroxime: 1 mg/0.1 ml (ESCRS Study)

Gatifloxacin: 100 mcg/0.1 ml

Moxifloxacin: 100 mcg/ 0.1 ml

Amphotericin B: 5-10 mcg/0.1 ml

Irrigating fluid
o
Vancomycin: 25-50 mcg/ml
o
Gentamycin: 0.008 mg/ml

Adrenaline tartarate: 1:10,000 (0.1 ml of 1:1000 is diluted with 0.9ml)

Pilocarpine: 0.1 ml of the drug (25 mg/ml) is diluted in 0.1 ml ringer lactate
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Ophthalmology Explorer
Dhaval Patel MD
Intrastromal Dosages

Voriconazole: 50 microgram/ 0.1 ml

Amphotericin B: 5-7.5 microgram/0.1 ml

Ciprofloxacin: 0.3 mg/0.1 ml

MMC: 0.02-0.04% for 15-30 sec to reduce post-operative interphase haze
Intravitreal Dosages





Antibiotics
o
Vancomycin: 1mg/0.1ml
o
Ceftazidime: 2.25mg/0.1ml
o
Amikacin: 400 migrogram/0.1 ml
o
Gentamycin: 200 migrogram/0.1 ml
Antifungals
o
Voriconazole: 50-100micrgram/0.1ml
o
Amphotericin B: 5 migrogram/0.1 ml
Antivirals
o
Ganciclovir (Cytovene): 200–400 mg/0.1 mL
o
Foscarnet (Foscavir): 1200 mg/0.05 mL
o
Cidofovir (Vistide): 20 mg/0.1 mL
Steroids
o
Dexamethasone: 400 mcg/0.1 ml
o
Triamcinolone acetonide: 1-4 mg/ 0.1 ml
Anti VEGFs
o
Pegaptinib MACUGEN: 0.3 mg in 0.09 ml pre-filled syringe
45
Ophthalmology Explorer
o
Dhaval Patel MD
Bevacizumab AVASTIN: 1.25 mg in 0.05 ml

1 ampoule: 0.2 ml

1 vial: 4 ml or 16 ml of 25 mg/ml
o
Ranibizumab LUCENTIS: 0.5 mg in 0.05 ml
o
VEGF Trap EYELEA: 0.05, 2, 4 mg in 0.05 ml
o
SiRNA: 70-300 mcg
Intravitreal Implants



Dexamethasone intravitreal implant (DEX implant; Ozurdex, Allergan, Irvine, CA)
o
delivers the steroid intravitreally for 6 months
o
consists of poly (lactic-co-glycolic acid), a DEgradable polyester and
dexamethasone
o
single-use applicator through a 22-gauge
o
uveitis and macular edema caused by retinal vein occlusion
o
350 µg and 700 µg version
o
Uses NOVADUR Delivery system
o
GENEVA (dexamethasone implant) study: Global Evaluation of implantable
dexamethasone in retinal Vein occlusion with macular edema (GENEVA) study
Vitrasert ganciclovir implant
o
poly(vinyl alcohol) and poly(ethylene vinyl acetate)
o
delivers the medication for approximately 32 weeks (8 months) and has been
shown to halt the progression of CMV
o
nondegradable
o
5/4.5 mg implant
o
Releases 1 mcg/ hour
o
Approaches concentration of 4 ug/ml intravitreal
Retisert fluocinolone implant
46
Ophthalmology Explorer




Dhaval Patel MD
o
blend of the drug with poly(vinyl alcohol) and methylcellulose
o
0.59 mg pellet embedded in a nonbiodegradable scaffold designed to be implanted
in the vitreous cavity via a sclerotomy and anchored by a suture to the eye wall
o
releases drug at steady state between 0.3 and 0.4µg/day for approximately 30
months
o
used most commonly for treatment of chronic non-infectious posterior uveitis.
o
Studied for DME also
Iluvien fluocinolone implant
o
narrow cylinder 3.5 × 0.37 mm
o
25-gauge
o
lowest dose format (0.2 µg/day)
o
higher-dose (0.5 µg/day) system
o
FAVOR (iluvien) study
I-vation triamcinolone implant
o
helical screw coated with triamcinolone acetonide that delivers the drug intravitreally
for 36 months
o
25-gauge
o
drug is entirely within the coating on the helical structure and not within the bulk of
the device
ECT CNTF Implant
o
which allows the intravitreal implantation of a chamber containing live cells
programmed to release CNTF
o
1.5 ng/day
o
possible efficacy for age-related macular degeneration (AMD) involving geographic
atrophy and for RP
o
2 years or more
ECT technology anti-VEGF implant
o
NT-503
47
Ophthalmology Explorer
o

Dhaval Patel MD
For ARMD
Brimonidine Intravitreal Implant
o
Patients With Geographic Atrophy Due to Age-related Macular Degeneration
(AMD)
o
This is a randomized, double-masked, dose-response, sham-controlled evaluation of
the safety and efficacy of brimonidine tartarate intravitreal implant in patients with
geographic atrophy from age-related macular degeneration. It is hypothesized that
the implant may promote the release of neuroprotective factors that may slow the
progression of retinal degenerative disease.
Iris Nodules & Pathology

Lisch nodule, neural crest hamartoma: NF 1

JXG nodules are composed of histiocytes and Touton giant cells: JXG

Koeppe nodules are collections of inflammatory cells, near pupillary margin: granulomatous
and non-granulomatous uvetis

Bassaca Nodules are seen at base: only in granulomatous uveitis (sarcoid, Tb, syphilis,
VKH); often look gelatinous

Brushfield spots are stromal hyperplasia: Downs syndrome

Berlin nodules are seen in angle: granulomatous uveitis
Laser Facts
Brief History

1917 - A. Einstein: Laser possible.

1958 - C.H. Townes, A.L. Schawlow: Theoretical basis for lasers.

1960 - T. Maiman: Built first laser.
48
Ophthalmology Explorer

1963 - C. Zweng: First medical laser trial (retinal coagulation).

1965 - W.Z. Yarn: First clinical laser surgery.
Dhaval Patel MD
Instrument Wavelengths
(Chronological order in nm)

SWAP: 440, blue light

Retinal Thickness Analyser RTA: green, 540-nm HeNe laser

Hertmann Shack‘s Aberrometer: 575 nm

HRT- CSLO: 670 diode

GDX-SLO: 780 diode

IOL Master: 780 diode

Lenstar: 820, SLD

Macular OCT (Posterior Segment OCT): 830

RNFL OCT: 810/850, SLD

AS-OCT: 1310, SLD

Swept Source OCT: 1050
Therapeutic Wavelengths
(nm)

Excimer laser: 193, Argon Fluoride (ultraviolet)

Excimer laser: 308, Xenon Cloride (ultraviolet)

Excimer laser trabeculostomy ELT: 308, Xenon Cloride

Argon blue-green: 488

Df Nd YAG: 512 (green)

ND YLF laser: 527 (in the treatment of diabetic macular edema)
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Ophthalmology Explorer

Argon green: 514

Yellow dye laser: 577 for DME

Krypton red or Dye red: 620-630

He Ne Gas laser: 632, for Laser interferometry

Rostaporphin PDT: 664 nm

Diode: 689, PDT (its verteporphin‘s peak absorption)

Ruby laser: 694, red

Infrared diode laser: 780, IOL Master

Transpupilary thermotherapy, DLCP: 810

subthreshold micropulse STMP diode 810nm: for DME

Intralase: Nd: YLF, wavelength is 1053 nm

Nd YAG: 1064

Ho YAG: 2100, used for laser thermokeratoplasty

Erbium YAG: 2940, for laser phacoemulsification

CO2 laser: 10600
Dhaval Patel MD
Laser settings for glaucoma

ND YAG PI: 500u, 5-15mJ, 12ns pulse, 1-3 pulse/sec

Argon PI: 50u, 1000mW, 0.1-0.2s,

Laser pupilloplasty: 200u, 0.2s, 400mW

Laser sphincterotomy: 50u, 0.01-0.05s, 1.5W

ALT: 50u, 100ms, 1000mW

SLT: 400u, 0.5-1.2mJ

DLCP: 810 nm, 2 mm from limbus, 8 spots per quadrent, 2000 ms, 1200-2000 mW
50
Ophthalmology Explorer
Dhaval Patel MD
Laser settings in Retina


PRP: df NdYAG
o
200-500 micron spot size
o
200-500 ms
o
200-500 mW
Macular Grid Laser: df NdYAG
o
50-100 micron spot size
o
50-100 ms
o
50-100 mW
Laser Parameters for PTK

Fluence: 160 ± 10 mJ/cm2

Repetition rate: 5 Hz

Ablation rate: 0.20-0.35 mm per pulse

Ablation diameter: 5.5–6 mm including a 0.5 mm transition zone

Ablation depths:
o
Epithelium 40 mm (default value) or as determined by pachymetry
o
Stroma: Depth of scar or opacity (postoperative corneal thickness should be at least
250 mm)
Modes of Laser
There are three modes of laser: continuous, Q-switched and mode-locked.
o
Laser from continuous mode has a constant power and is measured in watts.
o
Q-switched and mode-locked increases the energy by compressing the energy in
time and the energy is best measured in joules.
51
Ophthalmology Explorer
o
Dhaval Patel MD
Mode-locked laser compresses the laser more than Q-switched laser and therefore
produces more energy.
Laser Mediums

Solid state lasers have lasing material distributed in a solid matrix, e.g., the ruby or
neodymium-YAG (yttrium aluminum garnet) lasers. The neodymium-YAG laser emits
infrared light at 1.064 micrometers.

Gas lasers (helium and helium-neon, HeNe, are the most common gas lasers) have a
primary output of a visible red light. CO2 lasers emit energy in the far-infrared, 10.6
micrometers, and are used for cutting hard materials.

Excimer lasers (the name is derived from the terms excited and dimers) use reactive gases
such as chlorine and fluorine mixed with inert gases such as argon, krypton, or xenon.
When electrically stimulated, a pseudomolecule or dimer is produced and when lased,
produces light in the ultraviolet range.

Dye lasers use complex organic dyes like rhodamine 6G in liquid solution or suspension as
lasing media. They are tunable over a broad range of wavelengths.

Semiconductor lasers, sometimes called diode lasers, are not solid-state lasers. These
electronic devices are generally very small and use low power. They may be built into larger
arrays, e.g., the writing source in some laser printers or compact disk players.
Laser Safety Classification
The International Safety Classification of Lasers divides the lasers into 4 groups. Group 3 is
subdivided into 3a and 3b. Class 3b and above is damaging to the eye and their powers are
5MW and above. All lasers used in ophthalmology are classed as 3b and above. Safety goggles
should always be worn by people in the vicinity.
Class I: Do not emit hazardous levels.
Class II: Visible light lasers that are safe for momentary viewing but should not be stared into
continuously; an example is the aiming beam of ophthalmic lasers, or laser pointers.
Class III: Unsafe for even momentary viewing, requiring procedural controls and safety
equipment.
52
Ophthalmology Explorer
Dhaval Patel MD
Class IV: Also pose a significant fire and skin hazard; most therapeutic laser beams used in
ocular surgery are in this class
Latest Drugs

Lampalizumab: new monoclonal antibody that inhibits complement factor D, which is a ratelimiting enzyme of the alternative complement pathway, first positive treatment result for
patients with dry age-related macular degeneration and geographic atrophy.

Pazopanib is a small molecule lipophilic potent and selective multitargeted receptor tyrosine
kinase inhibitor of VEGFR-1, VEGFR-2, VEGFR-3, PDGFR-a/β, and c-kit that inhibits
angiogenesis.



o
Pazopanib eye drops
o
5-10 mg/ml TID
o
failed to reduce as-needed ranibizumab injections by ≥ 50%
AGN-150998:
o
Designed Ankyrin Repeat Proteins (DARPins)
o
Concept Study
o
Selectively binds to vascular endothelial growth factor-A with high binding affinity.
ROCK inhibitors:
o
Rho-kinase inhibitors (ROCK)  novel drug in glaucoma
o
human trabecular meshwork and Schlemm‘s canal cells to produce reversible
changes in cell shape, focal adhesions and decreases in stress of the actin fibers.
This resulted in an increase in permeability of the Schlemm cells‘ monolayer by 80%
o
decrease intraocular pressure by 25% to 32% and have a duration of action of 10 to
12 hours
o
ATS907, ATS8535, AR-12286, AR-13324, AMA0076
nitric oxide-donating prostaglandin F2-alpha analog  BOL-303259-X
o
comparable to latanoprost
53
Ophthalmology Explorer

Dhaval Patel MD
Aganocides: novel class of compounds that mimic the body‘s natural defense against
infection
o
NVC-422  Phase IIb clinical trial to treat adenoviral conjunctivitis.

Voclosporin (Luveniq): novel immunomodulatory drug that inhibits the calcineurin
enzyme, was originally developed to prevent organ graft rejection and to treat autoimmune
diseases. The chemical structure of voclosporin is similar to that of cyclosporine A, but with
a difference in one amino acid, leading to superior calcineurin inhibition and less variability
in plasma concentration.

Mapracorat:

o
selective glucocorticoid receptor agonist (SEGRA)
o
similar anti-inflammatory and immunosuppressive effects as the glucocorticoids but
with a decreased potential of the steroid side effects
o
Phase II study is evaluating its effectiveness in preventing the signs and symptoms
of allergic conjunctivitis. In addition, a Phase III study is underway for the
treatment of ocular inflammation after cataract surgery.
CF101: adenosine A3 receptor agonist
o
Adenosine has been shown to inhibit leukotriene B4 (LTB4), which is part of the
arachidonic acid cascade for the synthesis of prostaglandins and leukotrienes
o
For patients with moderate to severe dry eye

Lifitegrast: lifitegrast is a potent and selective small molecule drug being investigated for
the treatment of dry eye and ocular allergy. It inhibits T-cell inflammation by blocking the
binding of two key cellular surface proteins that mediate the chronic inflammatory cascade.

SMO Inhibitors (Smoothin): for advanced BCC
o
Cyclopamine (SMO Inhibitors):
54
Ophthalmology Explorer
o


naturally occurring sterol alkaloid, topical drug is in clinical trials

it is obtained from Veratum calnifornicum (rocky mountain corn lily) ingestion
of which causes serious malformation known as cyclopia and hence the
name given cyclopamine
Vismodegib (GDC-0449):

Synthetic small molecule

Orally active
o
Statins
o
Vitamin D3
Downstream SHH pathway inhibitors
o
o
Rapamycin (sirolimus)

Macrolide antibiotic

Inhibits MTOR in GLI1-transforme cells

No human stdies for BCC
MYCN anti-sence oligonucleotides



No human studies for BCC
BRAF inhibitors: for Malignant Melanoma
o
Sorafinib (pan BRAF)
o
PLX4032 (V600E-BRAF)
C-KIT inhibiors
o

Dhaval Patel MD
Imatinib
Sutent: Sunitimab
o
orally available multi-kinase inhibitor
o
Inhibits c-Kit, VEGFR, PDGFR etc
o
Activity against c-kit mutations that render OMs resistant to Gleevec
55
Ophthalmology Explorer
o
Synergistic effects with radiation and chemotherapy
o
Combination of Sutent, tamoxifan, cisplatin

Tegretin (Bexarotene): for CTCL (Mycosis Fungoides)

FOVISTA: Binds PDGF-B, phase 3 trials going on for wet AMD and CNVM.

Natalizumab: alpha 4 integrin

NT- 501
Dhaval Patel MD
o intra-vitreal implant is a Ciliary Neurotrophic Factor (CNTF) secreting encapsulated
cell device
o CNTF is a cytokine, which is a survival factor for various neuronal cells and seems to
prevent neurodegeneration.
o
CNTF may act through the IL-6 receptor.
o A semi-permeable membrane encapsulates genetically engineered human RPE cells
that secrete CNTF. It prevents host antibodies and immune cells from entering the
device but allows nutrients to diffuse in, to nourish the cells within and CNTF to
diffuse out. This holds promise for retinitis pigmentosa and dry age related macular
degeneration

Bevasiranib (CAND5) is a siRNA which switches off VEGF production, but clinical effect is
not seen till the preexisting VEGF is cleared. It has a potentially longer duration of effect
than currently available anti-VEGF agents. It is well tolerated at multiple doses.

Vatalanib is a VEGF receptor tyrosine kinase inhibitor given orally.

Fenofibrate is drug of the fibrate class used to treat dyslipidemia. Raises HDL and lowers
LDL and triglycerides and typically is used in combination with a statin. It lowers lipid levels
by activating peroxisome proliferator-activated receptor alpha (PPARα). PPARα activates
lipoprotein lipase and reduces apoprotein CIII, which increases lipolysis and elimination of
triglyceride-rich particles from plasma.

Fenretinide in Dry AMD: This drug is an oral vitamin A binding protein antagonist and is
being studied in patients with geographic atrophy (GA).It halts the accumulation of retinol
(vitamin A) toxins through affinity for retinol-binding protein. One of the hallmarks of dry
macular degeneration is the accumulation of lipofuscin that is responsible for drusen
formation and geographic atrophy. One year interim data showed that fenretinide slowed the
growth of geographic atrophy lesions by 45% in the 300 mg dose.
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Ophthalmology Explorer
Dhaval Patel MD

Copaxone (glatiramer acetate): weekly vaccination, Macular degeneration, Alzheimer‘s
disease and Multiple sclerosis

Citicholine (Cytidin-5-diphposphocholine): It is similar in action to levodopa. When
administered in adult patients with strabismic amblyopia (1gm\day i.m for 15 days), it has
showed improvement lasting over 6 months including improvement in contrast sensitivity
and VEP.
Mechanism of Action

Local anesthetics block the generation and conduction of nerve impulses

General Anesthetics: multiple

Fluoroquinolones: bactericidal agents that act by inhibiting DNA replication. They have dual
targets, topoisomerase II (DNA gyrase) and topoisomerase IV

Tetracyclines: broad-spectrum antibiotics that inhibit bacterial protein synthesis by binding to
the 30-S ribosomal subunit of the bacteria

Aminoglycosides: inhibit bacterial protein synthesis by binding irreversibly to the bacterial
30S ribosomal subunit.

Glycopeptides (Vancomycin and teicoplanin): inhibit peptidoglycan synthesis in the bacterial
cell wall by complexing with cell wall precursors

Macrolides: bacteriostatic agents that inhibit bacterial RNA-dependent protein synthesis by
binding reversibly to the 23S tRNA of the 50S ribosomal subunits

Chloramphenicol: bacteriostatic agent that inhibits protein synthesis by binding reversibly to
the peptidyltransferase component of the 50S ribosomal subunit and prevents the
transpeptidation process of peptide chain elongation

SMX-TMP: competitively inhibit the bacterial modification of p-aminobenzoic acid into
dihydrofolate, and trimethoprim inhibits bacterial dihydrofolate reductase

Bacitracin and gramidicin: Bacitracin disrupts bacterial cell-wall synthesis by inhibiting the
dephosphorylation of a lipid pyrophosphate, while gramicidin interferes more with cell
membrane permeability

Polymyxins: interact with the phospholipids of the bacterial cell membrane, which increases
the cell permeability and disrupts osmotic integrity. This process results in leakage of
intracellular constituents, leading to cell death
57
Ophthalmology Explorer
Dhaval Patel MD

Trifluridine: potent inhibitor of thymidylate synthetase and therefore inhibits DNA synthesis

Vidarabine: interfere with the early steps of viral DNA synthesis and arrests the growth of the
viral deoxynucleotide chain

Acyclovir: inhibits viral dependant TK (thymidine kinase)

Ganciclovir: competition with deoxyguanosine for incorporation into viral DNA

Polyenes: binds esterols in the fungal cell wall, forming ‗blisters‘ and causing lysis of the cell

Imidazoles: affect the formation of ergosterol needed by the cell membranes by inhibiting
the enzyme lanosterol 14 α-demethylase

Caspofungin: inhibits synthesis of B(1,3)-D glucan,a component of fungal cell wall
MIP

major intrinsic membrane protein

The most abundant membrane protein of the lens is intrinsic membrane protein 26 (MP26,
MIP). It is a lens-specific single polypeptide with a molecular mass of 28,200 kDa (263
residues) that makes up about 50% of the lens membrane protein.

MIP26 is a member of the aquaporin (AQP) family, members of which transport small
molecules such as water and glycerol.

MIP26 is termed aquaporin O

A locus for autosomal dominant cataracts has been mapped to chromosome 12q12-14.1
near the MIP gene
MMPs

MMP 1: collagen 1,2,3

MMP 2,9: collagen 4,5,7 and laminin

MMP 3: GAGs and Fibronectin

Only MMP 2 is found in normal cornea.
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Ophthalmology Explorer
Dhaval Patel MD
Molecular Weights

Sodium fluorescein: 376.27 daltons

Indocyanine green: 775 daltons

VEGF: 45kDa

Bevacizumab: 149 kDa

Ranibizumab: 48 kDa

Sodium Hyaluronate: 2–5 million d

Chondroitin Sulfate: 50,000 d

Silicone oil: 28,000 (1,000 centistokes)

Air: 29

Sulfur hexafluoride (SF6): 146

Perfluoroethane (C2F6): 138

Perfluoropropane (C3F8): 188

PMMA IOLs: 2.5 to 3 million Da

Acylic IOLs: 80 000 to 140 000 Da

Botulinum toxin: 900 000 Da
MUCins

Mucins are classified by the nomenclature MUC1–21 and are divided into secreted and
membrane-spanning categories
o
Membrane-spanning mucins consist of a short intracellular tail, membranespanning domain, and large, extended extracellular domain that forms the
glycocalyx.
o
Secreted mucins are either gel-forming or small soluble.

Gel-forming mucins are large molecules (20–40 million Da) secreted by
exocytosis from Goblet cells.

Small soluble mucins are secreted by the lacrimal gland.
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
MUC 1, MUC 4, and MUC 16: apical surface of the corneal epithelium

MUC 5AC and MUC 2: aqueous layer of the tear film (membrane-spanning, gel-forming
mucins)

MUC16 protein levels decreased in conjunctival epithelium and increased in tears of
patients with Sjogren's syndrome

MUC1 splice variants also play a role in dry eye

MUC5AC is the gel-forming mucin forming mucous layer backbone
NV %
BRVO
NVI: 1
NVD: 10
NVE: 30
Ischemic BRVO
40% of patients with an ischemic BRVO develop NVE or NVD.
60% of the patients with NVE-NVD develop VH/PRH.
Ich CRVO
NVI: 50
NVD: 30-35
NVE: 20-25
NVG: 45
CRAO
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Dhaval Patel MD
NVI: 20
NVD: 2
OIS
NVI: 67
NVD: 35
NVE: 8
EALES‘ DISEASE
NVI: 0.5-0.8 %
NVD: 10-18 %
NVE: 50 %
Sec RRD: 8-11 %
OCT Review



Time Domain OCT (TD-OCT)
o
Light echoes from each time delay measured sequentially
o
Slow acquisition speeds, high signal-to-noise ratio, poor view of the choroid
o
400 A-scans per minute, 6 B-scans per macula, 10-μm resolution
Spectral Domain OCT (SD-OCT)
o
Light echoes from each time delay, all measured simultaneously (high-speed
spectrometer)
o
Fast acquisition speeds, low signal-to-noise ratio, view to the choroid possible
o
52,000 A-scans per minute, 20-40 B-scans per macula (up to 100), 5-μm resolution
Enhanced Depth Imaging OCT (EDI-OCT)
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Ophthalmology Explorer


Dhaval Patel MD
o
Zero delay line (ZDL) positioned at the inner retina
o
The further from the zero-delay line (ZDL), the lower the signal resolution.
o
EDI moves the ZDL closer to the choroid; negative images when the ZDL is crossed.
o
Thinner layers permit deeper tissues to be closer to the ZDL.
Full Depth or Combined Depth Imaging OCT (CDI-OCT)
o
100 B-scans averaged for a single line scan.
o
50 in standard SD-OCT mode and 50 in EDI mode
o
Maximizes resolution of vitreoretinal and choroidal structures in a single scan
Swept Source OCT
o
Topcon DRI OCT-1 Atlantis
o
Longer wavelength light source (1050 nm)
o
Fast (100,000 A scans per second)
o
Uniform sensitivity, allowing excellent visualization of structures from vitreous to
sclera in one scan
o
Automated segmentation (7 layers)
o
100,000 A-scans per second, 1-μm resolution
o
12-μm wide scans (vs. 9- and 6-μm scans)
o
Image depth of 2.6 mm vs. 1.9 mm for EDI—even more ideal for choroidal tumors
Optic Nerve Segments
Longest segment  intraorbital
Shortest segment  intraocular
Segment with the most variable length  intracranial
Divided into three subsegments  intraocular
Most vulnerable to indirect trauma  intracanalicular
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Most redundant segment  intraorbital
The only segment not bathed in cerebrospinal fluid  intraocular
Orders of Abberations
0. Piston
1. Vertical and horizontal prisms
2. Myopia (positive defocus), hyperopia (negative defocus), Regular (cylindrical)
astigmatism
3. Coma, trefoil
4. Spherical astigmatism
5. rosette
6. pentacle, axial coma
Percentages % Primer

50% of patients with scleritis have systemic disease

Steroid-induced increases in intraocular pressure occur in about 6% of patients on topical
dexamethasone

30–50% of individuals with glaucomatous optic nerve damage and visual field loss have an
initial intraocular pressure measurement less than 22 mmHg.

sporadic inheritance of aniridia need to be evaluated for Wilms‘ tumor, which is associated
with 25% of cases.

BCC 3% mortality rate

83% of macular holes are idiopathic, and 15% are due to some sort of trauma

Deuteranomaly is present in approximately 5% of the population; deuteranopia,
protanopia, and protanomaly in 1% each; and tritanopia or tritanomaly in only 0.002%.
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
ACUTE ACG: 40–80% chance of an acute attack in the fellow eye over the next 5–10 years.

PPMD: Glaucoma is associated in 15%.

Axenfeld‘s syndrome is the anomaly with coincident glaucoma in 50% of cases.

Glaucoma in hyphema: Secondary glaucoma occurred in
o
13.5% of those eyes in which blood filled half of the anterior chamber,
o
in 27% of those eyes in which blood filled greater than half of the anterior chamber,
and
o
in 52% of those eyes in which there was a total hyphema.

Angle recession is found in 60–90% of patients with a traumatic hyphema

Up to 10% of patients with greater than 180 degrees of angle recession will eventually
develop a chronic traumatic glaucoma

Expulsive choroidal hemorrhage after cataract surgery: 0.2%

Retinal detachment after cataract surgery: 1–2%

PCO: 8-50%

HLA-B27–associated conditions account for approximately 45% of acute NGAU.

The incidence of HLA-B27 in the general population is 8%.

HLA B27 is present in 90% of patients with AS and 80% of those with Reiter‘s disease.

16% of patients of intermediate uveitis may develop multiple sclerosis

Sympathetic ophthalmia incidence:
o
perforating ocular injury (0.2%)
o
ocular surgery (0.01%)
o
80% of cases develop within 3 months of injury, and 90% develop within 1 year.

Among patients whose CD4+ count is less than 50 cells/mL, 20% per year develop CMV
retinitis.

A daily dose of >8 mg/kg/day of hydroxychloroquine produces retinopathy in 40% of cases.

Posttraumatic endophthalmitis incidence after penetrating ocular trauma: 7% of cases
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
complement factor H gene is a single nuclear polymorphism responsible for nearly 50% of
ARMD risk.

90% of infants who develop acute ROP undergo spontaneous regression

The risk of bilaterality in retinal arterial obstruction is approximately 10%.

Approximately 10% of patients with a BRVO will develop a retinal vein occlusion in the
fellow eye.

The prevalence of endophthalmitis is 1.4% after intravitreal triamcinolone injection.
However, this also includes cases of pseudoendophthalmitis. Excluding
pseudoendophthalmitis, the prevalence is approximately 0.6%.

The cilioretinal artery is present in up to 20% of individuals.

In uveal melanoma, if no epithelioid cells are present, the expected survival at 15 years is
72%. If epithelioid cells are present (mixed, epithelioid, or necrotic cell type), the survival at
15 years drops to 37%.

Liver metastases occur in 93% of patients who develop metastatic uveal melanoma. Other
sites include the lungs (24%) and bone (16%).

15% of eyes with symptomatic PVD develops retinal tear.

Untreated symptomatic retinal tear causes RD in 35-50% cases.

Pharyngoconjunctival fever: 30% keratitis
Epidemic keratoconjunctivitis: 80% keratitis
Phacomatosis
The 9 Phacomatosis: (there are total 9 phacomatosis which are numbered as follow)
1. neurofibromatosis type I - autosomal dominant - chromosome 17
2. NF type II - autosomal dominant - chromosome 22
3. tuberous sclerosis – autosomal dominant - chromosome 9
4. Sturge-Weber's syndrome – sporadic
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5. von Hippei-Lindau's syndrome - autosomal dominant - chromosome 3
6. Louis-Bar syndrome-autosomal recessive - chromosome 11
7. Wyburn-Mason syndrome - sporadic
8. Klippel-Trenaunay-Weber syndrome – autosomal dominant – chromosome unknown
9. cutis marmarata telangiectasia congenita - sporadic.
Phakomatosis is an outdated term and concept and term. Neither the AAO‘s monograph on
Inherited Diseases and the Eye (Traboulsi) nor the WHO‘s text on CNS Tumors includes the
term in the index. The WHO lists the disorders as familial cancer syndromes
Principles

CSLO: light projected toward the plane of interest through a conjugated set of pinholes
allows the light to reach the detector only from the desired plane, while light coming from all
other locations is blocked.

4 Δ prism test: Hering law and convergence, this test differentiates bifoveal fixation (normal
BSV) from a central suppression scotoma (CSS) in microtropia.

Faden procedure: suture the muscle belly to the sclera posteriorly so as to decrease the
pull of the muscle in its field of action without affecting the eye in the primary position.

VEP: recording of electrical activity of the visual cortex created by stimulation of the retina.

Laser: Stimulated emission of a photon of electromagnetic radiation

Nd-YAG: photodisruption.

Pinhole: It decreases size of blur circle.
A narrower pupillary aperture decreases the angle of the cone of light that produces the blur
circle. Ultimately the blur circle, albeit dimmer, is the size of the limiting cluster of
photoreceptors (i.e., pixel-size or grain-size equivalent). A stenopeic slit may be considered
as a line of pinholes.

Jackson Cross-Cylinder (JCC) test: placing the circle of least confusion on the retina

Keratometer: The cornea (with its overlying tear film) acts as a convex mirror to produce a
virtual, erect image of the ring. The size and position of the virtual image are measured
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
Scheiner‘s disc: Light enters the two pinholes and produces two images on the retina until
the light is brought to a focus.

OPD-Scan optical path difference scanning system: dynamic SkiaScopy and involves
acquisition of 1440 data points to produce a map of the optics of the whole eye

Allegretto wave analyzer: Tscherning principle of wavefront sensing.

Hartman-Shack devices: direction of propagation of light rays will be perpendicular to the
wavefront.

Non-contact pachymeters: optical low – coherence reflectometry
Radiation and Eye

The most sensitive ocular structure is the lens. (The minimum cataractogenic dose was
5.5 Gy and the maximum noncataractogenic dose was 11 Gy)

The sclera is the most resistant: easily tolerating >1000 Gy. Even up to 5000 Gy has
been given to the sclera without causing perforation

lacrimal gland, cornea, and conjunctiva: can tolerate up to 50 Gy (5000 rad) of radiation

retina tolerates: >55 Gy
o
The retinal pigment epithelial (RPE) cells were more radioresistant than
photoreceptors and RPE cell loss was only observed at doses of more than 1500
cGy
o
Most radioresistant in retina: Ganglion cell layer (?)
Rates

Aqueous humor production: 2 to 2.5 µL/min
o

Approximately 1% of the anterior chamber and 1.5% of the posterior chamber
volume of aqueous humor are replaced each minute
Outflow facility of fetal eyes:
o
0.09 µl/min/mmHg before 7 month
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Ophthalmology Explorer

o
0.3 µl/min/mmHg at 8 months
o
Average human value for C: 0.28 µl/min/mmHg.
Dhaval Patel MD
Pseudofacility:
o
0.06 µl/min/mmHg
o
20% of the normal human C value

Uveoscleral pathway: 0.5 µL/min

Tear fluid production: 1.2 µL/minute

Choroidal blood flow: 800 to 2000 mL/min/100 g of tissue

blood flow for the entire retina: 80 ± 12 µL/min

Tear Evaporation:
o
Normally: 0.14 µL/min
o
In dry eye: 0.43 µL/min
Recurrence %

Weiss procedure (transverse tarsotomy) alone for entropion: 11%

Pterygium Surgeries
o
Bare sclera type procedure for pterygium: 8% to 94%
o
Sliding Flaps for pterygium: 5%
o
Free flaps: 5%
o
Thiotepa: 11%
o
beta radiation:0% to 16%

surgical excision of CNV in pterygium: 38%

secondary membrane after Nd:YAG capsulotomy: 34-57%

meningioma: 22%
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Ophthalmology Explorer

idiopathic facial nerve palsy: 12%

Epithelioid sarcoma: 66%

IOID: 21% to 52%

orbital hemangiopericytomas: 30% upto 7 years

epithelioid hemangioma after surgical excision: 33%
Dhaval Patel MD
Refractive Indices

Water: 1.33

Cornea: 1.375 (for power calculation it is fudged to 1.337 to take into account negative
posterior curvature)

Aqueous 1.336

Lens cortex 1.386

Lens core 1.406

Vitreous 1.336

silicone oil: 1.400 and 1.405

PFCL: 1.27-1.33

IOLs
o
Silicon IOLs: 1.33

1st generation  Polydimethylsiloxane: 1.41

2nd generation  Polydimethyl diphenyl siloxane: 1.46

3rd generation  Biosil: 1.43 (Crystalens)
o
PMMA IOLs: 1.49
o
Acrylic IOLs: 1.55
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Ophthalmology Explorer

o
STAAR Surgical Collamer IOL, ICL: 1.45
o
CeeOn: 1.46
o
Array lens by AMO: 1.46
o
Akkommodative 1CU: 1.46
o
ThinLens (ThinOptX): 1.47 (acrylic)
o
Crystalens: 1.43
o
SmartIOL: 1.47
o
Light-Adjustable Lens: 1.43 (silicone)
o
Medennium Phakic Refractive Lens: 1.46
Dhaval Patel MD
Glasses
o
Crown glass: 1.52
o
CR-39: 1.49
o
Polycarbonate: 1.58
o
Flint glass: 1.66
Resolutions

Slit Lamp: 20 μm (Transverse)

Specular microscope: 2-5 μm (Lateral and Axial)

Confocal microscope: 1-2 μm (lateral), 5-10 μm (axial)

ASOCR: 18 um (axial), 60 um (transverse)

Stratus TD OCT: 8-10 um (axial), 20 um (transverse)

Cirrus FD/SD OCT: 5 um (axial), 16 um (transverse)

HR-OCT: 3 um (axial), 10 um (transverse)

SL-OCT: <25 um (axial), 20-100 um (transverse)
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Ophthalmology Explorer

USG: 150 um (axial), 450 um (transverse)

UBM: 25 um (axial), 50 um (transverse)
Dhaval Patel MD
RB Stats

RB1gene: 13q14

2 forms of mutations
o
o

Germline (Hereditary): 40%

Germline RB1 mutation in all cells

Mostly bilateral, 10-15% unilateral

More multifocality

All patients with bilateral RB have heretable form

Only 10% has family history
Somatic (Sporadic): 60%

Sporadic RB1 mutaion only in retinal cells

Unilateral only

Non heritable, no family history
Laterality
o
Unilateral: most cases ~75%  germline 15% and sporadic 85%
o
Bilateral: usually synchronous ~25%  germline mutation only
o
Trilateral: ~1%

90% non familial and 10% familial.

About 40% of all retinoblastomas are caused by germinal mutation and are therefore
heritable. (this occurs due to very high mutation rate of RB gene)

Deletion of 13q14 occurs in about 1% of cases and is associated with systemic
malformation.

The risk of offspring having RB is as follows.
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Ophthalmology Explorer
o
o
o

Dhaval Patel MD
if one parent has retinoblastoma:

40% of sibling are at risk

40% of offspring of affected patient
if both parents are normal and one sibling has unilateral retinoblastoma:

1% of sibling

8% of offspring
If both parents are normal and one sibling has bilateral retinoblastoma

6% of sibling (how?  due to gonadal mosaicism)

40% of offspring
RB is inherited as an autosomal- recessive trait at the cellular level; nevertheless,
retinoblastoma behaves clinically as if it has an autosomal-dominant inheritance pattern
with 90% penetrance.
Racial predilection of Diseases

Riley-Day syndrome: Ashkenazi Jews

Glucose-6-phosphate dehydrogenase deficiency: Mediterraneans

Oguchi disease: Japanese

Sickle cell hemoglobinopathy: African Americans

Diabetes mellitus, type 2: Pima Indians

Pseudoexfoliation: Scandinavian descent
Studies and Trials
(Includes important and latest facts only)
DR

DCCT: Diabetes Complication Control Trial
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



Dhaval Patel MD
o
Type 1 Diabetes Mellitus
o
No baseline retinopathy: Intensive control therapy reduced the risk of retinopathy by
76%.
o
Mild baseline retinopathy: Intensive control therapy slowed the progression of
retinopathy by 54% and reduced the development of severe nonproliferative
retinopathy by 47%.
UK Prospective Diabetes Study (UKPDS)
o
Type 2 Diabetes Mellitus
o
Tight glycemic control reduces risk of retinopathy.
o
A 1% decrement in HbA1c equated to a 31% reduction in retinopathy.
Action to Control Cardiovascular Risk in Diabetes (ACCORD)
o
Type 2 Diabetes Mellitus
o
Highly intensive glycemic control and combination of fenofibrate 160 mg q.d. and
simvastatin reduced the proportion whose retinopathy progressed by about one-third
at 4 years
Fenofibrate Intervention and Event Lowering in Diabetes (FIELD Study)
o
Type 2 Diabetes Mellitus
o
Fenofibrate 200 mg q.d. vs. placebo.
o
A FIELD study analysis found that fenofibrate reduces the first laser treatment by
31%; reduced macular edema by 31% and proliferative retinopathy by 30%.
Fenofibrate reduced the development or progression of retinopathy by reducing 22%
in all patients and 79% in patients with pre-existing retinopathy.
Effects of Intravitreal Ranibizumab on Diabetic Retinopathy in the RIDE/RISE Trials
o
Anti-VEGF Therapy
o
1:1:1: randomization  Sham: Ranibizumab 0.3: Ranibizumab 0.5
o
Ranibizumab therapy induces regression of diabetic retinopathy
o
Ranibizumab therapy retards the progression of diabetic retinopathy
o
Approximately 3-fold higher risk of PDR in shamtreated eyes
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Dhaval Patel MD
European controlled trial of lisinopril in insulindependent diabetes mellitus (EUCLID)
study
o
RCT studying whether lisinopril, an ACE inhibitor, would reduce the rate of diabetic
retinopathy progression in type-1 diabetes
o
showed that patients randomly assigned to lisinopril treatment had a lower risk of
diabetic retinopathy progression than controls.
o
However, the investigators found that at baseline patients in the lisinopril group had
lower baseline hemoglobin A1C levels than control patients.
DRCR.net
o
Protocol F: Observational Study of the Development of DME Following Scatter
Laser Photocoagulation

o
Clinically meaningful differences are unlikely in OCT thickness or visual
acuity following the application of pan-retinal photocoagulation (PRP) in 1
sitting compared with 4 sittings spread over 12 weeks. These results suggest
PRP costs to some patients, in terms of travel and lost productivity, as well as
to eye care providers could be reduced.
Protocol J: Laser-Ranibizumab-Triamcinolone Study for DME + PRP

The addition of 1 intravitreal triamcinolone injection or 2 monthly intravitreal
ranibizumab injections in eyes receiving focal/grid laser for DME and PRP for
proliferative diabetic retinopathy is associated with better visual acuity and
decreased macular edema by 14 weeks. Whether continued long-term
intravitreal treatment is beneficial cannot be determined from this study.
DME

DRCR.net
o
Protocol B: Randomized Trial Comparing Intravitreal Triamcinolone Acetonide
and Laser Photocoagulation for DME

o
Over 2 years, focal/grid photocoagulation is at least as effective and has
fewer side effects than 1- or 4-mg doses of preservative-free intravitreal
triamcinolone.
Protocol E: Pilot Study of Peribulbar Triamcinolone Acetonide for DME
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Ophthalmology Explorer

o
Diabetic Macular Edema and VEGF Trap-Eye: Investigation of Clinical Impact
BOLT
o

ranibizumab compared with sham injection
DA VINCI
o

Ranibizumab compared with laser
RIDE and RISE
o

Sixteen weeks after focal/grid laser for DME in eyes with a definite reduction,
but not complete resolution, of central edema, it is likely that somewhere
between 23% and 63% of these eyes will continue to improve without
additional treatment.
RESTORE
o

Intravitreal ranibizumab with prompt or deferred (≥24 weeks) focal/grid laser
is more effective through 2 years in increasing visual acuity compared with
focal/grid laser treatment alone for the treatment of DME involving the central
macula, although there is a small risk of endophthalmitis. Ranibizumab
should be considered for patients with characteristics similar to those enrolled
in this trial, including DME involving the center of the macula and decreased
visual acuity.
Protocol K: The Course of Response to Focal Photocoagulation for DME


The results demonstrated that intravitreal bevacizumab can reduce DME in
some eyes, but the study was not designed to determine whether or not the
treatment was superior to focal/grid laser.
Protocol I: Laser-Ranibizumab-Triamcinolone Study for DME

o
In patients with DME who have good visual acuity, peribulbar triamcinolone,
with or without focal photocoagulation, is unlikely to be of substantial benefit
to pursue with additional trials.
Protocol H: Phase 2 Randomized Trial of Bevacizumab for DME

o
Dhaval Patel MD
A Prospective Randomized Trial of Intravitreal Bevacizumab or Laser Therapy in the
Management of Diabetic Macular Edema
VISTA
o
VEGF Trap-Eye: Investigation of Safety, Treatment Effect, and Anatomic Outcomes
in Diabetic Macular Edema
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Dhaval Patel MD
Ozurdex Diabetic Macular Edema Study
o
1:1:1 (700 μg, 350 μg, sham injection)
o

Extended Follow-up of Patients With Macular Edema due to Retinal Vein Occlusion
(Diabetic Macular Edema) (RETAIN)
o
Group 1: RBZ TE + laser photocoagulation
o
Group 2: RBZ TE
o
Group 3: RBZ p.r.n.
ROP


CRYO- ROP
o
Treatment of avascular zone in threshold ROP reduces poor visual and structural
outcomes
o
31.6% cryo vs. 51.4% obs had poor structural outcome
o
44.4% cryo vs. 62.6% observed <20/200 and 27.2% vs. 47.9% had unfavorable
structural outcomes (p<0.001)
Light Reduction in ROP Study (LIGHT-ROP)
o

Supplemental Therapeutic Oxygen to Prevent prethreshold ROP (STOP-ROP)
o

Use of supplemental oxygen did not did not significantly reduce the number of infants
requiring peripheral ablative surgery.
High Oxygen Percentage ROP (HOPE-ROP)
o

A reduction in the ambient-light exposure does not alter the incidence of ROP
Not statistically different than outcome of STOP-ROP.
Early Treatment for ROP (ETROP)
o
Unfavorable visual outcome reduced from 19.8% to 14.3% (p<0.05) and unfavorable
structural outcome from 15.6% - 9.0% (p<0.0001) at 9 months in type I ROP.
o
Supported wait and watch policy for type II ROP.
o
Six year data consistent with 9 month data.
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Dhaval Patel MD
Efficacy of Intravitreal Bevacizumab for Stage 3+ Retinopathy of Prematurity (BEATROP)
o
significantly higher rate of recurrence with Zone I disease when treated with
conventional laser therapy compared to intravitreal bevacizumab (42 percent vs. 6
percent, p=0.003)
ARMD


AREDS 1
o
Vitamin C: 500 mg
o
Vitamin E: 400 mg
o
Beta carotene: 15 mg
o
Zinc: 80 mg
o
Cu: 2 mg
AREDS 2
o
Vitamin C: 500 mg
o
Vitamin E: 400 mg
o
Lutein 10 mg
o
Zeaxanthin 2 mg
o
Zinc: 25 mg
o
DHA: 350 mg
o
EPA: 650 mg
o
substituting lutein/zeaxanthin for beta-carotene in the AREDS formulation provides a
safer and more efficacious supplement for the treatment of AMD in those who are at
high risk of developing advanced AMD.

OMEGA study: Othera Eye Drops (antioxidant, anti-inflammation and anti angiogenic)

ENVISION Clarity trial in geographic atrophy: Pills for Dry AMD-Acucela (ACU-4429)
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Ophthalmology Explorer
Dhaval Patel MD

Role of CCR3 (chemokine receptor): Anti-CCR3 antibodies may prevent tube formation
prior to vascularization and reduce the proliferation of CECs following laser-induced injury.

ANCHOR=Anti-VEGF Antibody for the Treatment of Predominantly Classic Choroidal
Neovascularization in Age-Related Macular Degeneration
o

CATT=Comparison of AMD Treatment Trial
o
more systemic adverse events requiring hospitalization were found in the
bevacizumab-treated groups compared to the ranibizumabtreated groups
o

DAWN=Genetic Substudy of HORIZON
o

DAWN sought to explain differential response to ranibizumab therapy based on
genotype
DENALI=[US and Canada]
o
24-month randomized, doublemasked,multicenter trial in patients with subfoveal
choroidal neovascularization secondary to wet AMD (all lesion types)
o

EVEREST=[Asia] multicenter, double-masked, indocyanine green angiography-guided
randomized controlled trial with an angiographic treatment outcome designed to assess the
effect of verteporfin PDT alone or in combination with ranibizumab compared with
ranibizumab alone in patients with symptomatic macular polypoidal choroidal vasculopathy

PrONTO
o
first prospective study to investigate PRN anti-VEGF treatment of nAMD.
o
VA increased after 3 months by a mean of approximately 2 lines and was maintained
at that level through 2 years, with patients receiving an average of 5.6 injections in
year 1 and 4.3 injections in year 2.

FOCUS=RhuFab V2 Ocular Treatment Combining the Use of Visudyne® to Evaluate Safety

HARBOR=Study of Ranibizumab Administered Monthly or on an As-Needed Basis in
Patients With Subfoveal Neovascular Age-Related Macular Degeneration
o
The 0.5-mg dose of ranibizumab appears to be the most effective, but HARBOR also
showed us that in those rare cases in which we might need a higher dose 2.0 mg or
every-2-weeks dosing, it may be safe.
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
HORIZON=Extension Study to Evaluate the Safety and Tolerability of Ranibizumab in
Subjects With Choroidal Neovascularization Secondary to AMD or Macular Edema
Secondary to RVO

IVAN=Inhibit VEGF in Age-related Choroidal Neovascularization
o
compared bevacizumab and ranibizumab for age-related macular degeneration
o
bevacizumab was found to suppress systemic VEGF much more than ranibizumab
o
both medications are similarly effective

MARINA=Minimally Classic/Occult Trial of the Anti-VEGF Antibody Ranibizumab in the
Treatment of Neovascular Age-Related Macular Degeneration

MONT BLANC=[Europe] Randomized, double-masked, multicenter trial to compare the
efficacy and safety of same-day verteporfin PDT and intravitreal ranibizumab combination
treatment versus ranibizumab monotherapy in neovascular AMD

RADICAL=Reduced Fluence Visudyne Anti-VEGF-Dexamethasone in Combination for AMD
Lesions

SAILOR=Safety Assessment of Intravitreal Lucentis for Age-Related Macular Degeneration


o
PRN treatment with ranibizumab
o
Outcomes were not as good as in PrONTO
o
At 1 year, patients received an average of only 4.9 injections and had 9 office visits,
and mean VA declined continuously after patients completed the 3-dose initiation
phase
o
SAILOR identified prior stroke, cardiac arrhythmias, and a history of congestive heart
failure as risk factors for stroke while receiving anti-VEGF therapy
SUSTAIN
o
European study just like SAILOR in USA
o
mean number of treatments per patient was 5.6 at 1 year
o
mean gain of about 4 letters at 1 year
Lucentis Compared to Avastin Study (LUCAS)
o
―inject-and-extend‖ protocol
o
comparing bevacizumab and ranibizumab
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



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Dhaval Patel MD
Study to Observe the Effectiveness and Safety of Ranibizumab in the Real-life Setting
(LUMINOUS)
o
5-year, prospective, global, multicenter
o
wAMD, DME, BRVO, CRVO, CNV secondary to pathologic myopia (PM)
Pazopanib Eye Drops vs. Ranibizumab Intravitreal Injections for the Treatment of
Neovascular AMD
o
Pazopanib is a small molecule lipophilic potent and selective multitargeted receptor
tyrosine kinase inhibitor of VEGFR-1, VEGFR-2, VEGFR-3, PDGFR-a/β, and c-kit
that inhibits angiogenesis.
o
5-10 mg/ml TID
o
failed to reduce as-needed ranibizumab injections by ≥ 50%
VIEW 1 and 2
o
VIEW 1=[North America] VEGF Trap-Eye Investigation of Efficacy and Safety in Wet
AMD VIEW 2=[International]
o
Intravitreal Aflibercept Injection (IAI) in Neovascular AMD
o
BCVA increase of about 10 letters over baseline BCVA
ASSESS Study
o
intravitreal aflibercept injection (IAI) in subjects who were previously treated with
ranibizumab and/or bevacizumab for exudative AMD
o
2 mg of IAI every month for the first 3 months, followed by 2 mg once every 2 months
o
improved functional and anatomic endpoints in patients with exudative AMD
following previous anti-VEGF treatment.
MIVI-5 trial
o
Ocriplasmin in Exudative AMD
o
single intravitreal injection of 125 μg ocriplasmin or sham treatment
o
At Day 28, 24% of ocriplasmin-treated eyes achieved VMA resolution, compared to
12% of placebo-treated eyes
INTREPID Trial
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Dhaval Patel MD
o
looking at safety and efficacy of stereotactic radiotherapy in patients with age-related
macular degeneration who are receiving anti-vascular endothelial growth factor (antiVEGF) injections.
o
The 2-year follow-up data showed that radiotherapy treatment was associated with a
significant 25% reduction in the number of anti-VEGF injections over 2 years. "With
appropriate case selection, injections were reduced by 45% and there was a trend
for better visual acuity,"
trials comparing bevacizumab and ranibizumab
o
Comparison of AMD Treatment Trial (CATT)
o
IVAN
o
MANTA
o
Groupe d‘Evaluation Français Avastin versus Lucentis (GEFAL)
o
Lucentis Compared to Avastin Study (LUCAS)
Vitreomacular interface (VMI) diseases

Ocriplasmin Trials
o
MIVI
o
Single intravitreal injection of ocriplasmin (125 μg) with placebo injection in patients
with symptomatic VMA

VMA resolved in 26.5% of ocriplasmin-injected eyes vs. 10.1% placebo

VMA diameter ≤ 1500 μm: 34.7% resolution in ocriplasmin-injected
eyes; 14.6%, placebo

Total PVD at Day 28 was achieved in 13.4% of ocriplasmin-treated eyes vs.
3.7% placebo

Nonsurgical closure of macular holes was achieved in 40.6% of ocriplasmininjected eyes vs. 10.6% placebo

FTMH width ≤ 400 μm: closure at Month 6 (48.8% ocriplasmin vs.
18.2% placebo)
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Ophthalmology Explorer

o
o
FTMH width > 400 μm: 0% for both groups
Microplasmin in Children (MIC) trial

o
Dhaval Patel MD
175 μg was well tolerated when administered as a single intravitreal injection
in pediatric patients before vitrectomy
MIVI-5

Ocriplasmin for Treatment of Patients with VMA and Wet AMD

At Day 28, 24% of ocriplasmin-treated eyes achieved VMA resolution,
compared to 12% of placebo
OASIS Trial

Ocriplasmin for treatment of patients with symptomatic VMA including
macular hole
Glaucoma
(ONE CAGe)

OHTS: 20% lowering of IOP reduced risk of glaucomatous VF loss from 9.9% to 4%

NTGS: Reduction of normal pressures by 30% slowed the rate of glaucomatous progression
in a significant number of patients

EMGT: 25% decrease in IOP from baseline and maximum absolute 25mmHg reduced risk
of progression by 50%.

CIGTS: No difference in VF change between treatment modalities. IOP lower with surgery.
Higher rate of cataracts with filtering surgery

AGIS: Greater IOP reduction with trabeculectomy first. For black patients; better visual
preservation with laser first. For white patients better visual preservation with trabeculectomy
first. Low IOP associated with reduced visual field defect progression

GLT: Initial laser trabeculoplasty found as effective as initial topical Timolol to lower IOP and
preserve vision

CNTGS: found that by reducing the intraocular pressure by 30% the rate of visual-field
progression was reduced from 35% to 12%.

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ON

ONTT: Optic Neuritis Treatment Trial: Oral steroids alone did not have a significant
difference in visual recovery compared with the control group; however, the recurrence rate
of optic neuritis was increased. The IV steroid group had faster recovery of visual acuity and
a slight improvement in acuity over the control group.
NAION

IONDT: Ischemic Optic Neuropathy Decompression Trial: Patients in the surgery group did
no better when compared with the observation group regarding improved visual acuity of
three or more lines at 6 months. Approximately one third of the surgery patients had
improvement in acuity, whereas over 40% of the observation patients improved. Moreover,
surgery was associated with a higher risk of loss of three or more lines of acuity (surgery:
24%, observation: 12%). The IONDT conclusively states that optic nerve sheath
decompression is not effective.

MISC



VEGF Trap-Eye in CNV Secondary to Pathological Myopia (MYRROR)
o
IVT AFL treatment for myopic CNV started with 1 dose of IVT-AFL and induced
significant and clinically meaningful improvements in visual and anatomic parameters
compared with sham injections.
o
IVT-AFL is an effective treatment for myopic CNV.
The North American Symptomatic Carotid Endarterectomy Trial (NASCET)
o
For TMVL
o
demonstrated that endarterectomy is effective in reducing the risk of stroke in those
symptomatic patients with greater than 70% stenosis.
o
A subgroup analysis of those individuals with TMVL treated medically had 50% lower
risk of ipsilateral stroke than those patients with hemispheric TIA.
Astigmatic Reduction Clinical Trial (Arc-T) outcomes
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o
61% residual astigmatism 1 D or more
o
25% had no residual astigmatism
o
Greater effect with paired incisions, increasing age, longer incisions, smaller OZ
o
Second paired AK effect is not directly additive
Prospective Evaluation of Radial Keratotomy (PERK) outcomes
o
88% 20/40 or better uncorrected (all patients)
o
90% 20/40 or better (Preop 6D or less)
o
19% residual myopia of 1 D or more (all patients)
o
43% progressive hyperopic shift 1 D or more after 10 years
Surface Tension
Gases: 70
SiO (1000 cs): 21.2
SiO (5000 cs): 21.3
PFCL: 14
Specific Gravity


Silicon Oil
o
SiO (1000 cs): 0.971
o
SiO (5000 cs): 0.973
PFCL: 1.76-2.03
o
perfluoro-n-octane (C8F18): 1.76
o
perfluorodecaline (C10F18): 1.94
o
perfluorophenanthrene (C14F24): 2.03
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Surface Area

Globe: 22.86 cm2

Cornea: 130 mm2

Corneal endothelial cell: 250um2

Pars plicata: 600 mm2

Pars plana: 245mm2

Retina: 266 mm2

Fovea: 1.75-mm2

Disc: 2.34 ± 0.47 mm2

RPE: 240 mm2 at the fourth month 800 mm2 by 2 years of age

Conjunctival sac: 16 cm2 (roughly 17 times more surface area than the cornea)

Sclera: 16.3 to 17 cm2

Shunts (mm2)
o
o
Nonvalved

Molteno (Polypropylene): Single plate  135, Double plate  270

Baerveldt (silicone): 350, 250, 425
Valved

Krupin (silicone): 184

Ahmed (polypropelene): 184, 96, 364 (for double plate)
Survival Rates

craniopharyngioma: 10-year actuarial survival rates were 52% for subtotal resection alone
and 87% for subtotal plus radiation
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
Wilms tumor (nephroblastoma): 90% with multimodality approach

rhinocerebral mucormycosis: 14% when untreated, 57% with amphotericin B and surgery

Graft survival in FECD: 5 year and 10 year  97% and 90% respectively
Test Distances

Snellen‘s Test: 20 feet/ 6 meter

Near Vision: 14 inches or 1/3 meter

Hand Movement checking: 3 feet away

Bruckner test: an arms length

Hirschberg‘s Test: 14 inches (30 cm)

Teller acuity card test
o
0-6 months – 38 cm
o
7-12 months- 55 cm
o
>12 months-84 cm

Cardiff test: 50 cm or 1 meter

Catford drum test: 2 feet

OKNOVIS: 60 cm

STYCAR graded ball test: 10 feet in front of child

Sheridan letter test: 10 feet

Ishihara: 75 cm

Arden gratings plate for contrast sensitivity: 57 cm

Cambridge low contrast gratings: 6 m
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
Pelli-robsons chart: 1 m

Keeler LogMAR crowded test/ Glasgow acuity test: 3 m

ETDRS: 4 m

VisTech contrast chart: 3 m

FACT chart: 1 m

Amsler chart: 30 cm
Dhaval Patel MD
Thickness

Tear film: 7 um

CCT: 544 um (average)

Corneal epithelium: 50-90 um

Bowman‘s layer: 10-14 um

Corneal stroma: 500 um

Descemet‘s membrane: 4 um at birth and 10-12 um in adults
o
ABZ: 3 µm
o
PNBZ: 9 µm

Corneal endothelium: 6 um

posterior vitreous cortex: 100 to 110 µm

suprachorodial space: 30 µm

tarsal plate: 1 mm

inner limiting membrane of Elschnig: 50 nm

Bruch‘s membrane:145 nm in periphery and 55 nm at fovea
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VEGF Facts

VEGF is 45 kD molecular weight

Hypoxia is major regulator of VEGF expression.

EphrinA/EphA Interactions Modulate the Angiogenic Effects of VEGF

After successful PRP, intraocular concentration of VEGF decreases by 75%

VEGFR1: pericytes for vessels survival
VEGFR2: endothelium
VEGFR3: lymphangiogenesis




Pegaptanib
o
an aptamer, which is a single strand of RNA or DNA (RNA in the case of pegaptanib)
that folds up in such a way that its shape meshes with the VEGF molecule like a lock
and key.
o
There are several isoforms of VEGF, all of which are active in the angiogenesis
process. Pegaptanib selectively inhibits only the VEGF-165 isoform of VEGF, which
may explain the relatively lower efficacy of this drug compared with others in the
class.
Bevacizumab
o
full-length antibody that binds all isoforms of the VEGF-A family.
o
It was developed as a systemic antineoplastic therapy but has been used off-label for
neovascular AMD since 2005, first systemically and then intravitreally.
Ranibizumab
o
antibody fragment adapted from bevacizumab.
o
Like its parent molecule, ranibizumab binds all isoforms of the VEGF-A family.
Aflibercept
o
known as VEGF Trap-Eye
o
recombinant protein in which the binding domains of VEGF receptors 1 and 2 have
been combined with the Fc portion of IgG.
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o
Dhaval Patel MD
The molecule has a very high binding affinity for all VEGF-A isoforms as well as for
the related molecules placental growth factor-1 and factor-2 and VEGF-B
Vitreous cavity volume displacement
(ml)

Half of 5-mm sponge: 0.09–0.15

3 × 5 mm sponge: 0.11–0.20

5-mm round sponge: 0.14–0.22

#240 style (circumferential): 0.47–0.48

#276 style (circumferential): 1.08–1.13

#287 style (circumferential): 1.32–1.57

#280 style (circumferential): 1.82–1.88
Water Content

Cornea: 80%

Sclera: 70%

Lens: 65%

Vitreous: 99%

Aqueous: 99.9%

Contact Lenses

o
Low: 37.5% to 46% water, used for daily wear only
o
Medium: 46% to 58% water, used for both daily and extended wear
o
High: 59% to 76%, used for extended wear
IOLs
o
Hydrophobic acrylic: <2%
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o
Dhaval Patel MD
Hydrophilic Acrylic: 18% to 38%

Bausch and Lomb Hydroview IOL: 18% water

IOLtech MemoryLens: 20% water

Staar Collamer material IOL: 34% water
o
Acrylic PMMA IOLs: <1%
o
ThinLens (ThinOptX) lens: 18%
o
Acri.Smart lens: 25%
o
STAAR ICL: 34%
Basic Sciences

Copper accumulates in Descemet's membrane, the lens capsule, and other basement
membranes, whereas iron accumulates in basal epithelial cells.

Intact oculovestibular reflexes in a patient with gaze palsy implie a supranuclear
disturbance.

Optic pit forms as outpounchings from diencephalon part of neural tube.

At birth, weight of the lens is 90 mg. it increases 2mg/year.

The dimensional characteristics of the optic nerve can be remembered with the mnemonic
phone number 125-1017, which stands for the lengths of the intraocular (1), intraorbital (25),
intracanalicular (10), and intracranial (17) portions of the optic nerve.

The inferior nasal retinal fibers cross in the anterior chiasm and were thought to loop
anteriorly in the contralateral optic nerve before traveling posteriorly, leading to the term
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Wilbrand's knee (NI=Nasal + Inferior). It is now thought that Wilbrand's knee may be an
artifact.

the inferior fibers of the optic radiations pass extremely close to the internal capsule.

Compared with plasma, aqueous is slightly hypertonic and acidic. Aqueous has a marked
excess of ascorbate (15 times greater than that of arterial plasma) and a marked deficit of
protein (0.2% in aqueous as compared to 7% in plasma).

The four divisions of the optic nerve head correlate roughly with a four-part blood supply.
o
The surface fiber layer is supplied mainly by branches of the central retinal artery.
o
The prelaminar region is supplied by capillaries of the short posterior ciliary
arteries.
o
The lamina cribrosa region is also supplied by vessels that come directly from the
short posterior ciliary arteries to form a dense plexus in the lamina.
o
The retrolaminar region is supplied by both the ciliary and retinal circulations,
with the former coming from recurrent pial vessels. The central retinal artery provides
centripetal branches from the pial region.

Loteprednol is an ester steroid with minimal to no cataractogenous properties. The other
steroids are ketone steroids, which have more potential to cause a cataract.

The superior orbital fissure transmits the branches of cranial nerve V1, III, IV, and VI.
Cranial nerve V2 enters the orbit through the inferior orbital fissure.
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
The optic pits first appear on day 23 of gestation. Evagination of the optic vesicle occurs
on day 25 with induction of the lens on day 28. Closure of the optic fissure occurs on day
33.

Lid colobomas do not occur from failure of the fetal fissure to close.

Anterior and posterior radii of curvature
o
Lens: 10 and 6 mm
o
Cornea: 7.8 and 6.5 mm

Myelination of the optic nerve starts in the seventh month of gestation and is completed
about 1 month after birth. Myelination starts at the LGB optic tract chiasm and
progresses toward the lamina cribrosa.

The inferior or superior muscular branches of the ophthalmic artery provide all or part
of the blood supply to all the extraocular muscles except the lateral rectus. The lateral rectus
blood is supplied by a single vessel derived from the lacrimal artery. Each rectus muscle,
except the lateral rectus, receives two anterior ciliary arteries that communicate with the
major arteriole circle of the ciliary body.

The trigeminal nerve divides into three segments: ophthalmic (V1), maxillary (V2), and
mandibular (V3).
o
The ophthalmic nerve is divided into three branches: nasociliary, frontal, and
lacrimal. O-NFL

o
The frontal nerve, a branch of the ophthalmic (V1) segment, divides into the
supraorbital and supratrochlear nerves. F-SS
The maxillary (V2) segment divides into the infraorbital, zygomatic, and superior
alveolar nerves. The zygomaticofacial and zygomaticotemporal nerves are branches
of the zygomatic nerve (V2). M-IZS
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
Bowman's membrane represents a compact collagen layer at the anterior aspect of the
corneal stroma. It is not a true basement membrane.

All of the recti muscles originate from the annulus of Zinn. The superior oblique and levator
palpebrae originate superior to the annulus.

The accessory lacrimal glands are the basic secretors. These include the glands of
Krause and Wolfring. The reflex secretor is the main lacrimal gland.

Although type I collagen exists in the stroma, it is associated with normal stroma. Type III
collagen is associated with stromal wound healing.

The reasons for relatively miotic pupils in infancy include immaturity of dilator pupillae
muscle.

The optic nerve is generally myelinated to the lamina cribrosa 4 to 6 months before
foveal maturation.

Congenital colobomas of the eyelids are associated with Goldenhar

The lower lids are more frequently involved by congenital ectropion and congenital
entropion.

70% of pregnant women are seronegative for toxoplasmosis. Placental transfer of
organism is common in the newly infected mother; however, many infected infants will not
have systemic manifestations.

most common clinical finding in infants with congenital rubella syndrome  SNHL
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
Although children with congenital rubella syndrome may develop either cataract or
glaucoma, their coincidence in an infant is rare.

In rubella cataract after surgery, Excessive rebound uveitis is caused by live virus
retained within the residual lens cortex.

The most common congenital infection in humans is CMV. Approximately 2% of human
infants are infected. Most cases are silent.

In HSV, A posterior inflammatory component is far more common in congenital
disease, with severe retinitis and vitritis. This is unusual in acquired disease but may be the
cause of some cases of acute retinal necrosis.

Microphthalmia is an unusual manifestation of congenital syphilis.

Hutchinson's triad of congenital syphilis: peg-shaped teeth, eighth nerve deafness, and
interstitial keratitis.

Pharyngoconjunctival fever (adeno type 3) generally spares the cornea.

M Pathway subserves: motion & pursuit, direction, speed judgement, coarse stereopsis
Occipitoparietal: magnocellular, WHERE pathway  localization and movement
P Pathway subserves: fine acuity, shape, colour, fine stereopsis
OccipitoTemporal: parvocellular, WHAT pathway  color, shape and pattern

The central retinal artery arises from the ophthalmic artery after ophthalmic artery passes
through the optic canal. The central retinal artery then dives into the center of the optic
nerve where it travels until it exits from the optic nerve head.
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
Volume of conjunctival cul de sac is 7 uL. Ideal drop size should be 20 uL. Ideal drop
viscocity should be 12-15 cps.

The ciliary ganglion receives three roots:
1. A long sensory root that contains sensory fibers from the cornea, iris, and ciliary body—
this root delivers sensation to the central nervous system (CNS) through the nasociliary
nerve (V1).
2. A short motor root that carries preganglionic parasympathetic axons to the iris
sphincter—these are the only fibers that synapse here. This root arises from the lower
division of CN III, the oculomotor nerve (which also supplies the inferior oblique).
3. A sympathetic root that innervates the blood vessels of the uvea—this root arises from a
plexus around the internal carotid artery and passes through the optic foramen (with the
ophthalmic artery).

The sclera, like the cornea, is virtually avascular except for two areas: (i) the superficial
vessels of the episclera, and (ii) the intrascleral vascular plexus located immediately
posterior to the limbus.

The trabecular meshwork consists of thin, perforated connective tissue sheets arranged in
a layered pattern. The connective tissue ―beams‖ are lined by a monolayered
endothelium. The trabecular meshwork is derived from the neural crest tissue.
Animal outflow studies have shown that the juxtacanalicular trabecular meshwork (TM),
which is immediately proximal to Schlemm's canal, is the primary limiting factor for
outflow facility.

Retinal pigment epithelium (RPE) cells in the foveal area are taller, more closely packed,
and have more and larger melanosomes, contributing to the relative hypofluorescence of
this area during fluorescein angiography.

Rods and cones are characterized by three components: the synaptic body, the inner
segment, and the outer segment. The synaptic body of a rod is called a spherule, whereas
that of the cone is called a pedicle. Photopigment is stored in discs in the outer segments.
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In rods, the discs are not attached to the cell membrane, but cone discs are continuous with
it.

PBG: Intraretinal processing occurs from photoreceptors to bipolar cells to ganglion
cells, with modulation by horizontal (outer plexiform layer) and amacrine (inner plexiform
layer) cells.

Approximately 120 million rods and 6 million cones interact with 1.2 million ganglion
cells in an eye. Therefore, the ratio of rods to cones is approximately 20:1. (Some studies
cite a ratio as low as 12:1.)

A cilioretinal artery contributes to the vascular supply of the retina in approximately 50% of
individuals and 30% of eyes. In 15% of individuals, it contributes to macular circulation.

The outer plexiform layer is composed of interconnections between photoreceptor
synaptic bodies, horizontal cells, and bipolar cells. The inner plexiform layer is composed
of connections between bipolar cells, amacrine cells, and ganglion cells.
Outer PHoB
Inner BAG

Levator is served by a single subnucleus. It sits dorsal, central, and at the inferior end of the
group of subnuclei that compose the two third-cranial nerve nuclei. The superior recti have
two subnuclei, each controlling the contralateral nerve. In contrast, the inferior obliques
and the medial recti each have individual subnuclei that control the ipsilateral nerves. The
superior oblique is served by the fourth nerve. The lateral rectus is supplied by the sixth
cranial nerve.

The pupillomotor fibers of the third cranial nerve run in the inferior division, which carries
them to the ciliary ganglion. They are among the axons in the periphery of the nerve,
making them easily susceptible to compression.
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Dhaval Patel MD
Neural crest cells give rise to ciliary musculature, corneal stroma, and endothelium (but not
corneal epithelium), most of the sclera (except for a temporal portion which is of
mesodermal origin), choroidal stroma, some of the orbital bones, orbital cartilage, orbital
connective tissue, nerve sheaths, and uveal melanocytes. Extraocular muscles form from
paraxial mesoderm.
Blood vessel endothelia, extraocular muscles, and temporal sclera are all mesodermal in
origin. The mesoderm also contributes to the formation of the vitreous. The pupillomotor
muscles are neuroectodermal in origin. The trochlea originates from the neural crest.
Conjunctival epithelium is derived from surface ectoderm, but the substantia propria is
derived from the neural crest.

Sporadic aniridia is associated with Wilms' tumor (usually because of deletion of the
PAX6 gene and the adjacent Wt1 Wilms' tumor gene). Aniridia is not typically found in
patients with autosomal-dominant Wilms' tumor.

Aqueous humor provides most of the glucose needed by the endothelium, stroma, and
epithelium. Hydrophobic molecules penetrate the epithelium most easily, whereas
hydrophilic molecules penetrate stroma more easily.

Topical administration of type E and type F prostaglandins, as well as arachidonic acid,
causes miosis. High doses of prostaglandins will cause an increase in intraocular pressure
(IOP). Low doses of some prostaglandins, in contrast, appear to lower IOP in some
animal species.

By blocking phospholipase, corticosteroids effectively inhibit both the lipoxygenase (LOX)
and cyclooxygenase (COX) pathways.

Enzymes in Aqueous:
Carbonic anhydrase, although present in only trace amounts in the aqueous humor, has a
high enough turnover that it is felt to be functionally significant.
Hyaluronidase is present in aqueous humor and may participate in the regulation of
resistance to aqueous outflow.
Lysozyme is present and provides antibacterial protection.
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Lactate dehydrogenase, not normally detectable in aqueous humor, may be a marker for
retinoblastoma.

Lens epithelium cells are located anteriorly underneath the lens capsule. Epithelium cells in
a ring around the anterior lens, or the germinative zone, exhibit the highest level of
deoxyribonucleic acid (DNA) synthesis (the S phase in the cell cycle). Newly formed cells
migrate toward the lens equator, where they differentiate into lens fiber cells.

The water-soluble proteins of the lens are divided into three types of crystallins that are
fractionated into four electrophoretic groups.
Alpha crystallins are the largest, with molecular weights of >500,000 daltons.
Beta crystallins are the most abundant, making up approximately 55% of the water-soluble
protein.
Gamma crystallins are the smallest.

Unlike the retina, the lens can function without oxygen but not without glucose,
primarily because the lens mostly relies on anaerobic glycolysis to generate adenosine
triphosphate (ATP). In a glucose-depleted environment, the lens will become hazy after
several hours.

Syneresis (vitreous liquefaction) is associated with a focal decrease in collagen
concentration. Both collagen and hyaluronic acid concentration are decreased by 20% to
30% in myopic eyes (axial length >26 mm).

Vitamin A, stored hepatically, is transported in serum as all-trans retinol. Conversion
between aldehyde and alcohol (and vice versa) occurs in the photoreceptors, whereas
the trans to cis isomerization takes place in the retinal pigment epithelium (RPE).

Photoreceptors are more active electrically (depolarized) in the dark! With light
absorption, transducin (via phosphodiesterase [PDE]) lowers cyclic guanosine
monophosphate (cGMP) concentration, which hyperpolarizes the cell and decreases
synaptic exchange with bipolar cells.
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
Clinically, carbonic anhydrase must be >99% inhibited to decrease aqueous humor
secretion significantly.

Aspirin causes inhibition of cyclooxygenase (COX); therefore, arachidonic acid is
diverted to the lipoxygenase (LOX) pathway. This is thought to be the underlying
mechanism for the asthma attacks and hypersensitivity reactions (by increased production
of leukotrienes).

Cromolyn sodium is a mast cell stabilizer and has no direct antihistaminic effect (receptor
blockade). It is only effective if used prophylactically.

Probenecid competitively inhibits penicillin excretion by the kidney.

Angioid streaks can be seen in hemochromatosis but not in sarcoidosis.

Combination of Angioid streaks and pseudoxanthoma elasticum is known as GronbladStrandberg syndrome.

Because of increasing resistance to vancomycin, the Center for Disease Control and
Prevention (CDC) has recommended avoidance of the use of empiric vancomycin in
patients with neutropenia unless clear evidence for a beta-lactam-resistant Gram-positive
infection can be demonstrated.

Serum purine levels in patients with Down's syndrome are typically elevated. The
enzymes required for the biosynthesis of purities are coded by genes present on the long
arm of chromosome 21. The presence of a third set of these genes presumably results in
the elevation of serum purine levels.

The expression of multiple discrete anomalies in various organs caused by a single gene
mutation is termed genetic pleiotropism.
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The iris sphincter receives parasympathetic innervation by the inferior division of the
oculomotor nerve (which also supplies the inferior oblique muscle) (These are the only
fibers that synapse in the ciliary ganglion).
The iris dilator is supplied by sympathetic fibers running with the nasociliary and long
ciliary nerves, branches of the first division of the trigeminal nerve (V1).

Motor units, defined as one terminal motor nerve branch and all the muscle fibers it serves,
are smaller in the extraocular muscles than anywhere else in the body. This permits the
finest control of force generation and muscle action possible.

There are approximately 20 short posterior ciliary arteries, which enter the sclera in a
circle around the optic nerve. There are two long posterior ciliary arteries, which usually
enter the sclera on either side of the optic nerve at the 3- and 9-o'clock positions. The
posterior ciliary arteries supply the uveal tract, the sclera, conjunctiva, and cilioretinal
arteries. There are seven anterior ciliary arteries, which provide muscular feeding
branches (supplying the extraocular muscles) and terminate in the major arterial circle of the
iris.

Ganglion cells are the first retinal cells to differentiate into a recognizable level.

Rod outer segment shedding in animal models will persist even after several days in the
dark. On the contrary, dark deprivation (i.e., constant light adaptation) will rapidly ablate
normal rod disc shedding.

Rod OS shedding occurs in morning and Cone OS shedding occurs in evening.

The cell most commonly used for karyotypic analysis is the T lymphocyte.

Nuclear third-nerve palsy may feature contralateral upgaze palsy because SR is served
by a contralateral brainstem subnucleus.
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
Pregnancy usually lowers intraocular pressure. Uveoscleral outflow is enhanced.
Lowered episcleral venous pressure may contribute to enhanced trabecular outflow as
well.

The level of retinopathy before pregnancy is the strongest risk factor for significant
progression during pregnancy. NPDR to PDR 5%

The corneal and retinal pigment epithelium (RPE) damage is limited to historical reports of
patients treated with much higher dosages of tamoxifen, where the chance of toxicity is
much higher. Ocular toxicity has not been reported with cumulative doses of <10 g.

As per DCCT, once progression occurs, patients who rigorously control their blood sugars
are twice as likely to recover, compared with less-controlled diabetics. Therefore, “early
worsening” is a temporary effect among patients undergoing intensive treatment.

5% of patients with diabetes will develop asymmetric retinopathy. (difference of two
stages is taken as asymmetric)

Studies have shown that preoperative (72 hours) antibiotic reduces bacterial counts to a
greater degree than 3 days of preoperative povidone-iodine. Adding povidone-iodine at
the time of surgery exerts a synergistic effect. Some studies have suggested that saline
flushes actually increase bacterial colony counts.

Cigarette smoking has been most strongly associated with choroidal neovascularization.
(also with RPE hyperplasia as per beaver dam study.)

55 minutes is the shortest duration of cataract surgery that has resulted in photic
maculopathy.
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
A human metabolite of a bioflavonoid found in grapefruit juice, but not in orange juice,
inhibits several cytochrome components of the P450 isozyme group.

Naphazoline and antazoline are traditional antihistamines.
Levocabastine is a cyclohexylpiperidine. It is topical H1 blocker with no chemical or
structural relation to other antihistamines.
Lodoxamide is a mast cell stabilizer used for prophylaxis of atopic conditions, not for acute
treatment.
Ketorolac is a traditional nonsteroidal anti-inflammatory drug.
Nordihydroguaiaretic acid (NDGA) is a lipoxygenase (LOX) inhibitor.

Hyperbaric oxygen (HBO) exposure: myopic shift, cotton-wool spots, cataract.
Hyperbaric oxygen (HBO) has been used successfully to help treat: arterial gas
embolism, chronic cystoid macular edema, rhino-cerebral-orbital, mucormycosis, radiation
optic neuropathy. NOT CRAO.

Carbonic anhydrase inhibitors are most likely to be of benefit in disorders of the retinal
pigment epithelium (RPE) and significantly less likely to help in cases of primary retinal
vascular disease.

CME: Fishman and colleagues have established that 500 mg/day of acetazolamide is
more effective than 250 mg/day. They have subsequently demonstrated that methazolamide
50 mg twice daily is less effective than acetazolamide.

No urine test results have been found to be affected by recent fundus angiography.
Cortisol, thyroxine, and quinidine are affected for up to 3 hours, with digoxin being affected
for up to 12 hours. Serum creatinine levels may be affected, but this appears to be shortlived (<3 hours).
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
Interferon retinopathy: cotton-wool spots and retinal hemorrhages, particularly around
the optic disc, which usually appear within 3 months of the onset of therapy. Ischemic optic
neuropathy and proliferative retinopathy have also been reported.

Flurbiprofen is used to prevent prostaglandin-mediated miosis during surgery.

Calcification of Retinoblastoma is due to: RPE Hyperplasia
Calcification of Cysticercosis is due to: Calcified Corpuscles

Lens nuclei are not retained in Alport‘s syndrome

Lacy vacuolization is a pathologic finding of glycogen-filled cysts in the Iris pigment
epithelium: seen in diabetes.

In pathology specimen, a fold at the ora serrata-is a fixation artifact found in newborn eyes
called Lange's fold.

Corneal ―Swirl‖ Keratopathy
Chloroquine
Suramin (used in AIDS patients)
Tamoxifen
Amiodarone

Transient Myopia
Sulfonamides
Tetracycline
Perchlorperazine (Compazine)
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Steroids
Carbonic anhydrase inhibitors

Rifabutin is a derivative of rifampin that may create an autoimmune abnormality and is
associated with a high prevalence of uveitis that can be bilateral, recur with rechallenge,
and improve upon withdrawal.

Steroids can be a cause and a treatment of Pseudotumor cerebri.

Drugs that can give nystagmus include:
Barbiturates
Tranquilizers
Anticonvulsants

Drugs that can cause RPE dysfunction
(hydroxyl) chloroquine, phenothiaztne and desferroxamine

Drugs that can cause macular oedema
nicotinic acid, latanoprost and topical adrenaline

Drugs that can cause crystalline retinopathy
tamoxifen, methoxyflurane and canthaxanthine

Iris Heterochromia
o
Congenital:

Hypochromic: congenital Horner‘s syndrome, Waardenburg‘s syndrome,
Hirschsprung‘s disease, Perry- Romberg hemifacial atrophy.
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
o
Dhaval Patel MD
Hyperchromic: ocular or oculodermal melanocytosis, iris pigment epithelium
hamartoma.
Acquired:

Hypochromic: acquired Horner‘s syndrome, juvenile xanthogranuloma, iris
metastatic carcinoma, Fuchs‘ heterochromic iridocyclitis, stromal atrophy
(glaucoma or inflammation).

Hyperchromic: siderosis, hemosiderosis, chalcosis, medication (topical
prostaglandin analogues for glaucoma), iris nevus or melanoma, iridocorneal
endothelial syndrome, iris neovascularization

Ciliary processes are the most vascular structure of the eye.

The trem protan, deutran and tritan are derived from Greek word meaning first, second
and third.

The term CALOTTE is used in ocular histopathology for the two hemispheres which are
cut from the globe.

Visual field background illumination = 31.5 apostilb

Photopic maximum sensitivity = 555 nm
Scotopic maximum sensitivity = 507 nm

Fischer–Khunt spot: (Senile scleral plaque) blue–gray area of hyalinized sclera anterior to
horizontal rectus muscle insertions in elderly individuals

Purkinje shift: Shift in peak spectral sensitivity from photopic (555 nm, cones) to scotopic
(507 nm, rods) conditions.
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
Recurrent nerve loop of Axenfeld: Described in 1895 by T. Axenfeld was a nerve that
makes a loop in the sclera anteriorly. The nerves travel through the sclera usually originating
from the long ciliary nerves and some may approach the surface of the sclera about 1-6
mm from the limbus. The nerves bend 180 degrees creating a mushroomed loop at the
surface. They may produce symptoms of irritation and tenderness.

Vigabatrin (VGB) is an irreversible inhibitor of gamma-aminobutyric acid (GABA)
transaminase and is a highly effective antiepileptic drug for treating partial-onset seizures
and infantile spasms.
Vigabatrin is associated with visual field defects (as many as one-third of patients) but the
mechanism is unknown.
It should be avoided in patients with pre-existing visual field defect. Ophthalmoscopy
appearance in patients taking vigabatrin includes narrowing of the retinal arterioles,
wrinkles on the retina surface and optic atrophy in the presence of visual field defects.
It causes a characteristic form of peripheral retinal atrophy and nasal or „„inverse‟‟ optic
disc atrophy in approximately 10% of children being treated with VGB resulting in
severely constricted visual fields.
Discontinuation of VGB should be strongly considered in these children.

Steps to reduce OCR- OculoCardiac Reflex: use of atropine and light sedation

The inner layer of the optic cup contains the pluripotent retinal progenitor cells, which
differentiate in a specific chronologic sequence and defined histogenic order into the final
seven retinal cell types. In general, the RGCs differentiate first, followed by the cone
photoreceptors, amacrine cells, horizontal cells, and finally, the rod photoreceptors, bipolar
cells, and Müller cells. GCAHRBM  God Can Always Help Revealing Best Messages.

High doses of digoxin can cause objects to appear yellow (xanthopsia). Withering
reported visual side effects of digoxin in his classic paper in 1785

Emsley Fincham test: The stenopic slit is kept in front of the eye and the patient is asked to
look at a light source. The slit is then moved in front of the eye
In conjunctivitis and in glaucoma, there is no fan effect. In cataract, there is fan effect.
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Colored halos caused by cataract (lenticular) seem to break into a moving fan but not
that caused by glaucoma (corneal) which only become slightly dim. Moreover, the VIBGYOR
of the rainbow is within outwards in lenticular halos and without inwards in corneal halos.
This is because; in glaucoma colored halo is due to corneal edema which is
homogeneous. In cataract, it is due to accumulation of water droplets in lens; which
is a heterogeneous phenomenon.

Pseudomonas is a rare commensal.

C.diphtheria is not a part of normal commensals. C.xerosis and other corynebacteria
are there.

Space of Mortegiani: extends posteriorly over ONH.

Nerves which escapes after retrobulbar block: trochlear, conjunctival sensory nerves and
few sympathetics

Optic nerve has 1.5 million axons whereas trochlear nerve has 1500 axons. Its smallest
cranial nerve.

Orbital lobe of lacrimal gland is anterior and Palpebral lobe is posterior. REMEMBER
This. Else you can remember orbital lobe is superior and palpebral lobe is inferior.

Lacrimal gland structures are post-septal structure whereas lacrimal sac structures are
pre-septal.

Russel bodies: plasma cells (activated B lymphocytes)

Morula cell (of Mott): Contains multiple grape-like Russell bodies
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Inflammation:
Acute (exudative): Polymorphonuclear leukocytes, Mast cells and eosinophils
Chronic (proliferative):
Nongranulomatous: Lymphocytes and plasma cells NLP
Granulomatous: Epithelioid histiocytes, giant cells GEG

Doxycycline changes the lipid viscosity of the meibomian gland secretions, improving
oil secretion from the gland into the tear film. This superficial lipid layer is needed to keep
the tears from evaporating too quickly.

Color of the Fundus: The color of the fundus depends on the melanin content of the retinal
pigment epithelium, the melanin content of the melanocytes in the choroidal stroma, and
the hemoglobin in the choroidal and retinal vasculature. The melanin contribution to the
color parallels the complexion of the patient's skin and hair, the fundus being darker in black
races and lighter in whites.

Cilioretinal vessels originate from the circle of Zinn, which is formed around the optic nerve
in the sclera from the short posterior ciliary arteries.

The small white light reflex at the center of the fovea centralis is produced by the
reflection of the ophthalmoscope light from the concavity of the fovea.

With the pupil widely dilated, the peripheral fundus can be seen with the direct
ophthalmoscope up to the equator only. You cannot see beyond the equator by direct
ophthalmoscope. The patient must be instructed to move the eyeball in the appropriate
direction so that each quadrant of the retina can be brought into view.

Fixative for electron microscope is: glutaraldehyde
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
Drug for myopia: pirenzepine, atropine (in research)

Chlamydia
o
Both DNA + RNA
o
No cell wall
o
No energy production
o
Elementary body is infective form
o
Basophilic cytoplasmic inclusion body
Dhaval Patel MD

White cyst of pars plana on HP Slide is diagnostic of multiple myeloma.

The human retina is able to detect a difference of 1 nm in wavelength between blue-green
(490 nm) and yellow (585 nm).
At the violet (430 nm) and red (650 nm) ends of the visible spectrum a greater difference
exceeding 4 nm is required for a difference to be appreciated.

The optic nerve fibers are separated from the retinal layers by a ring of glial tissue, the
intermediary tissue of Kuhnt.
The continuation of this glial tissue, the border tissue of Jacoby (glial), separates the
choroid from the optic nerve fibers
Ring of collagenous tissue of scleral derivation, the marginal tissue of Elschnig (fibrous,
temporal), lies outer to the glial sheaths.

Striated muscle of the leg can contain several hundred muscle fibers per motor unit; in the
extraocular muscles, each axon innervates 3 to 10 fibers. This dense innervation
provides for precise fine motor control of the extraocular muscles resulting in high velocity
ocular movements, necessary in saccades, (up to 1000 degrees per second) and very
accurate pursuits (velocities of 100 degrees per second) and fixations.
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
Afferent information regarding extraocular muscle proprioception is thought to be mediated
by a receptor that is unique to extraocular muscle, the myotendinous cylinder (palisade
ending) in contrast to Muscle spindles and Golgi tendon organs of typical striated muscles.

Metarhodopsin II is the rate limiting step in visual cycle.

Thickest BM of body is lens capsule.

STYCAR: Sheridan/Screening Tests for Young Children and Retardates, Sheridan 1973

Zone S/ Smooth Zone:

o
Anterior border - transition from trabecular to corneal endothelium and the
termination of Descemet's membrane
o
Posterior border - elevation formed by the oblique insertion of uveal trabeculae into
limbal stroma
o
50-150 microns
Ligamentum Hyaloideocapsulare of Wieger: insertion of cilioposterior fibers, tractus
hyaloideus, peripheral boundary of Berger‘s space.
Spatium retrolentalis Berger: potential space between posterior lens capsule and patellar
fossa=anterior cortical gel
Canal of Petit: Space between posterior zonules and anterior cortical gel. May contain
pigment, blood, air
Orbiculohyaloidal Space of Hannover: between anterior and posterior zonules.
Cloquet‘s Canal: posterior to central cortical gel, funnel to area of Martegiani.
Area of Martegiani: circular vitreous cortical defect above optic nerve=papilla

The uvea has mechanical attachments to sclera
o
at the entry of the long and short posterior ciliary vessels
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o
the border layer of Jacoby (choroidal, prelaminar level) at the disc,
o
the vortex veins and
o
the major perforating branches of the anterior ciliary arteries at the ciliary body level.
o
The main attachment of the uvea however is at the scleral spur where the
longitudinal muscle of Brucke (tensor choroidalis) inserts.
o
These attachments determine the configuration of choroidal elevations:

shallow anterior=supraciliary

quadrilobed=to vortex insertion

kissing=scleral spur to short posterior ciliaries.
Clinicians‘s limbus: Transition of clear cornea to opaque sclera (corneolimbal junction)
Histologist‘s limbus: transition of regular corneal stromal lamellae to irregular scleral
stromal lamella. (Peripherally convex line)
Pathologist‘s limbus: tissue roughly between external and internal scleral sulcus, 12mm wide. Internal scleral sulcus bordered by end of Decemet‘s membrane (corneolimbal
junction) and scleral spur (limboscleral junction)

No epithelium covers the anterior iris surface.
Anterior border layer is composed of fibroblasts and melanocytes.
Both iris sphincter and dilator are neuroectodermal derivations.
Sphincter and dilator are attached to each other at the central Fuchs‘ spur and peripheral
Michael‘s spur.

Longitudinal muscle of ciliary body is also known as Brucke‘s muscle or tensor
choroidalis.

Lens zonules (capsular fibers) can be divided into
o
Cilioanterior
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o
Cilioequatorial
o
Cilioposterior
o
orbiculoanterior and orbiculo posterior: these fibers originate from the dentate
processes of the retina, form the orbiculohyaloidal interspace of Hannover, rest
on the anterior hyaloid and ―suspend‖ the anterior vitreous.
Subretinal space borders: border tissue of Kuhnt (posterior cul-de-sac) – ora serrata
(anterior cul-de-sac)
Suprachoroidal space borders: border tissue of Elschnig (posterior cul-de-sac) –
scleral spur (anterior cul-de-sac)

Middle limiting membrane: junctional complexes between rod spherules and cone
pedicles.
Mueller cells elaborate the internal limiting membrane which is their cell base (base in,
apex out).
The Mueller cell apex points to the photoreceptors and elaborates the external limiting
membrane, a desmosomal junctional system.

The inner 1/3 and outer 2/3rd of OPL is separated by the middle limiting membrane
which is composed of synapses and their junctional systems connecting the axons of rods
and cones (inner fibers of Henle) to the outer neurons. The middle limiting membrane
denotes the limit of retinal capillaries as well as a barrier to exudates.

Dentate processes of the retina are more prominent nasally.
Blessig Ivanoff cysts: Cystoid degeneration of retina is more prominent temporally.

Typical peripheral cystoid degeneration (TPCD)
o
inevitable in adult eyes
o
The cystoid spaces develop first at the outer plexiform layer. If these spaces
coalesce, typical degenerative retinoschisis results.
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o
In most cases, this is without clinical consequence.
o
Very rarely, a retinal detachment can develop in the presence of holes in the inner
and outer layers of the schisis cavity.
o
In contrast, reticular cystoid degeneration is less common and develops in the
nerve fiber layer.
Vitreous components, 3-fold origin:
Lens (surface ectoderm), retina (neuroectoderm) and vascular endothelium (mesoderm)
Primary vitreous <6 weeks (<13mm): "Cellular", Hyaloid canal remnants
Secondary vitreous <8 weeks (13-65mm): "Vascular", Vitreous body
Hyaloid vessels, collagen fibrils (Mueller cell footplates) and hyaluronic acid
(neuroectodermal) More fibrils and hyaluronic acid
Tertiary vitreous at >12 weeks (>65mm): Zonules and Marginal Bundle of Druault =
future vitreous base.

The anterior margin of the optic cup is called the ―Marginal sinus of von Szily‖. It advances
on the posterior surface of the iris stroma.
Pupillary ruff: Marginal sinus of von Szily reaches pupil in the 4th month and forms the iris
sphincter and dilator. If it fails to do so, the condition is called Aniridia.

Internal ulcer of von Hippel: If endothelial (Descemets) defect occurs related to incomplete
separation of lens

The differentiation of the macula is not complete until 4–6 months after birth.
Ganglion cell nuclei are initially found directly over the foveola and gradually are displaced
peripherally, leaving this area devoid of accessory neural elements and blood vessels as
neural organization develops to adult levels by age 6 months.
This delay in macular development is one factor in the inability of newborns to fixate, and
improvement in visual activity parallels macular development.
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
The superior orbital fissure at the orbital apex lies between the greater and lesser wings
of the sphenoid bone.

Paranasal Sinuses:
o
All paranasal sinuses are normally present at birth (apart from the frontal sinus which
is rudimentary until 2 years of age).
o
All sinuses are lined by a pseudostratifieci columnar ciliated epithelium, which aids
the passage of mucus into the nasal cavity.
o
The maxillary sinus drains via the hiatus semilunaris into the middle meatus of the
nose.
o
The anterior and middle ethmoidal air cells, along with the frontal air cells, also drain
into the middle meatus of the nose.
o
The posterior ethmoidal air cells drain into the superior meatus whereas the
sphenoidal air cells drain into the sphenoethmoidal recess.
o
All lymph drainage from the paranasal sinuses is to the submandibular nodes,
except the sphenoidal sinuses and posterior ethmoidal sinuses which drain into
the retropharyngeal group of nodes.

The osseous canal for the nasolacrimal duct is formed by the maxilla, the lacrimal bone, and
the inferior nasal concha; it opens into the inferior meatus of the nose.

The conjunctiva becomes continuous with the keratinised skin epithelium along the
posterior margins of the tarsal gland openings and not at the grey line, which lies
anterior to these openings.
The grey line marks the tissue plane along which the eyelid may be split into an anterior
lamella consisting of skin, subcutaneous tissue and orbicularis, and a posterior lamella
consisting of the tarsal plate and conjunctiva.

The stratified squamous epithelium of the palpebral conjunctiva becomes a stratified
columnar layer in the bulbar region before again becoming stratified squamous in
continuation with the corneal epithelium.
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
The final diameter of the cornea is determined by the diameter of the optic cup.

Corneal Development:
o
The initial step in comeal development is the production of a bilayered epithelium
and basement membrane separate from a bilayer (or occasionally a trilayer) of
endothelial cells and associated basement membrane
o
At approximately 7 weeks gestation a primitive stroma is formed, which is
infiltrated by fibroblasts producing; collagen fibrils.
o
By the third month the stroma is a structure of 25—30 layers a thin Descemet‗s
membrane is present and the endothelium is now a single layer.
o
Bowman's layer is the last of the five corneal layer to form.
o
Corneal nerves are present by five months.
o
The cornea has reached its adult form by seven months.
o
The cornea is not transparent throughout development but becomes so gradually
as its stmcture becomes more ordered.

Cold and pain are the only stimuli of the corneal epithelium.

The palisades of Vogt are formed by epithelial cells, which are thrown into folds by the
subepithelial connective tissue at the limbus.

The ciliary epithelium is a bilayered cuboidal epithelium that forms an integral part of the
blood aqueous barrier.
The two cell layers lay apex to apex, the inner layer being rich in golgi apparatus and rough
endoplasmic reticulum while the outer layer contains numerous melanocytes.
There are numerous tight junctions between the cells of the inner layer but not between cells
of the two layers.
The basement membrane of the inner layer is continuous with the internal limiting
membrane of the retina, whereas the basement membrane of the outer layer is continuous
with that of the retinal pigment epithelium.
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
The sphincter and dilator muscles arise from the anterior epithelial layer.

Sclera is thickest (1 mm) at its posterior pole, thins to 0.6 mm at the equator and is thinnest
(0.3 mm) immediately posterior to the tendinous insertions of the recti.

The outer plexiform layer is the watershed region of the retina: structures that lie peripheral
to this layer (rods and cones in the outer nuclear layer) receive their nutrients by diffusion
from the choroidal circulation, whereas the inner two-thirds of the retina receive nutrients
directly from the central retina artery and its tributaries.

parasympathetic fibers to the lacrimal gland:
superior salivatory nucleus- nervus intermedius (glossopalatine) nerve- geniculate
ganglion- greater superficial petrosal nerve- joined by the secondary sympathetics from
the deep petrosal nerve and enter the pterygoid canal (vidian canal)- vidian nerve
emerges from the pterygoid canal and enters the sphenopalatine ganglion
(pterygopalatine) where the primary parasympathetic fibers synapse and then exit as
secondary parasympathetic fibers- join the zygomatic nerve which sends a
communicating branch that enters the lacrimal gland


Medial Canthal Area
o
The medial canthal tendon has anterior and posterior portions.
o
The anterior portion attaches to the frontal process of the maxillary bone and serves
as the origin of the superficial head of the pretarsal orbicularis.
o
The posterior portion inserts on the posterior lacrimal crest and fossa. The
posterior limb of the medial canthal tendon, the deep head of the pretarsal
orbicularis, and the deep head of the preseptal orbicularis muscles are important in
maintaining apposition of the eyelids to the globe.
o
The lacrimal sac is positioned anterior to the orbital septum and, therefore, does not
lie within the orbit.
Lockwood's ligament (Lockwood's suspensory ligament)
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o
suspensory system for the globe.
o
It is the lower eyelid retractor system with contributions from intermuscular septae
and Tenon's capsule.
o
Posteriorly, it arises from fibrous attachments to the inferior side of the inferior rectus
muscle and continues anteriorly as the capsulopalpebral fascia (lower eyelid
retractors).
o
Medial and lateral horns extend to attach to the retinacula.

The medial retinaculum attaches to the posterior lacrimal crest

The lateral retinaculum attaches to the lateral orbital tubercle of Whitnall.
These tissues form a suspensory hammock for the globe.
The superior transverse ligament, or Whitnall's ligament
o
arises from the compaction of the sheath of the anterior portion of the levator muscle.
o
Medially, it arises from the connective tissue of the trochlea.
o
Laterally, it attaches to the capsule of the orbital lobe of the lacrimal gland and to the
lateral orbital wall above the lateral orbital tubercle.
o
There are extensions to the medial and lateral retinacula. This structure acts to
change the direction of pull of the levator muscle from horizontal to vertical and
serves to limit the elevation of the eyelid.
o
Although Whitnall's ligament attaches to the fascia on the superior and medial
surfaces of the lacrimal gland; it does not pass anteriorly to the lacrimal gland.
o
The lacrimal gland is divided into orbital and palpebral lobes by the lateral horn of the
levator aponeurosis.
The lacrimal gland is supported by four fascial structures
o
Soemmering's ligaments
o
Whitnall's ligament
o
Inferior ligament of Schwalbe
o
lateral horn of the levator palpebrae aponeurosis.
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The orbicularis muscle
o
Divided into orbital parts and palpebral parts (pretarsal, preseptal)
o
The orbital portion is involved in forced eyelid closure. It originate from the anterior
medial canthal tendon and periosteum.
o
The palpebral portion of the muscle is also responsible for reflex blinking (as
opposed to the orbital portion, which ―screws‖ the eyelids tightly together)
o
The pretarsal portion arises from the posterior lacrimal crest and anterior limb of
the medial canthal tendon. The lateral portion of the pretarsal muscle becomes the
lateral canthal tendon. The deep head of the pretarsal muscle (tensor tarsi muscle
of Horner) encircles the canaliculi to facilitate tear drainage.
o
The preseptal orbicularis originates from the fascia around the lacrimal sac and
posterior lacrimal crest. Superficial origins arise from anterior fibers of the medial
canthal tendon. Laterally, it forms the lateral palpebral raphe overlying the lateral
orbital rim.
o
It is a muscle of facial expression that is derived from the second branchial arch
and is therefore supplied by a branch of the facial nerve.

Lateral wall is the strongest orbital wall.

Commonest soluble protein in the vitreous is acid glycoprotein.

Multifocal ERG charts 61-103 focal retinal points.

Foveola: 1.25 degrees
Fovea: 5 degrees
Macula: 15-20 degrees

C-peptide is the marker for insulin production.
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O2 tension
o
Aqueous: 72 mmHg
o
Tear with lid closed: 55 mmHg
o
Tear with lid open: 155 mmHg

Minimum O2 tension to prevent cornea from swelling is 11 mmHg.

RQ of cornea is 1.

Ocular immune privilege

Dhaval Patel MD
o
Complement inhibition by membrane cofactor protein (MCP), decay-accelerating
factor (DAF), and CD59
o
Clonal deletion: Fas ligand expressed in uveal tissue causes deletion of the Fas+ T
cells that enter that tissue and recognize antigen
o
Clonal anergy: TGF-ß2, free cortisol, and IL-1 receptor antagonist
o
Immune deviation: ACAID or anterior chamber-associated immune deviation.
o
T-cell suppression: TGF-b, a-MSH, VIP, CGRP, MIF, free cortisol
Gene Therapy
o
Demonstration of efficacy/cureof severe combined immunodeficiency (―bubble-boy
disease‖) using ex vivo gene replacement has provided proof of principle for gene
therapy.
o
Glybera: approved to treat lipoprotein lipase deficiency
o
For recessive diseases, replacement with ―wildtype‖ gene or gene correction
resulting in production normal enzyme: eg, RPE-65, peripherin/RDS(Prph2)
o
For dominant disease, neutralization of toxic ―dominant‖ substance (eg, ribozyme
therapy for rhodopsin mutants causing dominant RP)
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
o
Current trials are going on for AMD, Leber congenital amaurosis type2, Stargardt
disease, choroideremia, Usher syndrome 1B, choroideremia, and retinitis
pigmentosa due to MERTK mutations.
o
Gene Therapy for Wet AMD

Retinostat: Phase I Testing in 2013

sFlt01: Phase I Testing in 2013
Classification of Cell Death
o
Apoptosis
o
Autophagy
o
Necrosis
Caspase-Dependent Apoptosis
o
External death signals such as tumor necrosis factor (TNF) or Fas ligand (FasL)

o
o
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Dhaval Patel MD
RIP kinase (RIPK) signaling is closely connected to both the extrinsic
caspase signaling pathway and the NF-κB survival pathway
intrinsic signals such as mitochondria damage and reactive oxygen species (ROS).

Apoptosis-inducing factor (AIF) is an intrinsic factor involved in initiating a
caspase-independent pathway of apoptosis

play a role in photoreceptor cell death after RD
Caspases are also involved in pyroptosis, a distinct mechanism of cell death
associated with inflammation
Neuroprotection Strategies
o
Caspase inhibition

o
Fas-mediated apoptosis pathway becomes activated after RD, and inhibition
of Fas activation (with anti-FAS-receptor antibodies) can decrease caspase-9
activity
Combined inhibition of apoptosis and necroptosis: RIPK-mediated necrosis
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o
Ciliary neurotrophic factor (CNTF): act through the IL-6 receptor
o
Brimonidine
Dhaval Patel MD

Rabl's lamellae: radiating pattern of lens fibres in periphery, fibers being more uniform
beneath the epithelium and becoming thicker and irregular as they age and approach the
nucleus

Arrestin is also known as S-antigen.

Oguchi's disease is a nonprogressive autosomal-recessive congenital stationary night
blindness that maps to chromosome 2 with candidate gene in that region is the arrestin
gene.

Resistance to diffusion of solutes and bulk fluid flow are of considerable importance to
maintaining normal corneal function (resistance to diffusion of solutes and fluid flow:
epithelium [2000] ≫ endothelium [10] > stroma [1])

The nasolacrimal duct derives from ectodermal tissue in the nasolacrimal groove between
the lateral nasal and maxillary processes. This tissue is known as the nasolacrimal
ectodermal cord. Mesenchymal tissues from the maxillary process cover the ectodermal
tissue medially, before it canalizes.
The central cells of the cord degenerate until there is a superior membrane composed of
canalicular and conjunctival epithelium, as well as an inferior membrane of nasolacrimal and
nasal epithelium. These superior and inferior ends are usually patent at the time of birth.

The lacrimal gland arises from an outpouching of the conjunctiva as a modified salivary
gland.

Primary lymphoid organs: Thymus and bone marrow
Secondary lymphoid organs: Lymph nodes, spleen, MALT
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Cmax: The maximal concentration of drug in the tissue is Cmax.
Tmax: The time to reach a maximal level of drug in the tissue is Tmax.
Area under the curve (AUC): The AUC yields the total amount of drug absorbed from an
applied dose. The bioavailability of a drug is computed from the AUC, which is most
important in determining therapy for chronic medication.

Ocular Effects of PGs
o
D: Stimulates vasodilation and chemosis
o
E1, E2: Increase inflammation, Increase intraocular pressure, Increase capillary
permeability, Stimulate vasodilation, Stimulate miosis
o
F2: Reduces intraocular pressure, Has minimal effect on inflammation, Has minimal
effect on miosis
Optics & Refraction

In streak retinoscope, when para-stop is at Down position, rays coming out are Divergent
from convex/ plane mirror. If position of para-stop is up, rays coming out are convergent
from concave mirror.

Hard contact lens fitting:
1. Base curve = flattest K + 0.5 (for tear lens)
2. Convert manifest sylinder to minus lens
3. Disregard the cylinder
4. Correct for vertex distance if sphere is >= 4D
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5. Substract +0.5 tear lens (created by fitting +0.5 overflattened contact lens)

Toric Transposition for CL:
The steps for toric transposition is as follow:
1. Make sure the cylinder has the same sign as the base curve
2. Obtain the required power of the spherical surface by subtracting the base curve power
from the spherical power. Here the result is +3-(-5) = +8.00DS
3. Specify the axis of the base curve and this axis is 90 degrees to that of the required
cylinder. The result in this case is: -5.00DC axis 180.
4. Finally add the required cylinder to the base curve power with its axis. The result is -5 (1.00) = -6.00DC axis 90.
Example: –2.00 DS/–0.50 DC*90° Base Curve + 5.00
Rule No 1: Sign of cylinder should be same as sign of base curve. Sign of cylinder needs to
be changed by simple transposition.
–2.50 DS/+0.50 DC*180°
Rule no 2: Power of new sphere= –2.50–(+5.00) = –7.50 DS
Rule no 3: Power of cylinder no 1= +5.00 DC*90°
Rule no 4: Power of cylinder no 2= + 0.50 DC + (+5.00 DC) = + 5.50 DC*180°
• Practical problem of Near Add: Point to be remembered is that ‗add‘ is algebraically
added to the spherical power for distance and there is no change in power and axis of
cylinder. So when you are prescribing separate glasses, near vision glasses contains add of
near on whatever distance correction patient has.
•
Most commonly used material for glasses is CR-39 (C stands for Columbia and R stands
for resin). This material can withstand heat up to 100° C. Its refractive index is 1.498.
Chemically it is Allyl Diglycol Carbonate. (ADGC)
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•
V-value Constringence or Abbe‘s number: The degree to which the material has the
same refractive index for different wavelengths of light. Lenses made with lower V values
more quickly show rainbows, color fringes and degradation of best acuity when the eye
turns towards the periphery of a spectacle lens, the effect being proportional to the power of
lens. In simple language it is a positive value that indicates the degree of transverse
chromatic aberration. High V-value means low dispersive power and vice versa. Thus
Crown glass has V-value of 59 and CR-39 has V-value of 57.8 and thus patient does not
complain of colored fringes due to their low dispersive power. In contrast-high index lenses
and polycarbonate lenses have a low V-value thus high dispersive power and cause colored
fringing of objects.
•
A lens with base curve of 6D is known as deep meniscus lens and with a base curve of
1.25D is known as Periscopic lens.
•
Photochromatic lenses darken on exposure to light and become colorless in dark again.
This is because silver chloride crystals which change into free silver on exposure to
sunlight. This free silver forms silver colloids which absorb UV radiations to cause darkening
of lenses. In indoor conditions silver particles, combined with trapped halides and silver
halide crystals are reformed and lens appears clear.
These lenses darken only in sunlight but not in artificial light because UV radiations are
required for the darkening effect. Hence car windows which block UV rays also render these
lenses less effective inside the car.
•
AR coating decreases reflection of incident light on lens and increases its transmittance. As
the AR coating absorbs ultraviolet rays hence less light is available for activation of
photochromic property of lens. Thus a photochromic lens with AR coating becomes less
dark on exposure to light as compared to a normal photochromic lens.
•
Balance Lens: This type of lens is used to balance the weight of the other lens in the
spectacle frame where one eye is practically blind. For better cosmetic appearance, the
balance lens power and style should match the other lens.
• Lenses with refractive index between 1.64 and 1.73 are called high index lenses
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
Vergence is defined as the reciprocal of the distance from a reference point (in meters) to
the point of focus. By convention, divergence is given in minus (-) vergence power and
convergence is given in plus (+) vergence power.

A diopter is a unit of accommodative amplitude; it describes the vergence of a waveform
and describes the vergence at a specific distance from the source; and it is also defined as
the power of the lens. A diopter is the reciprocal of the distance in meters.

Converging lenses have real/inverted images that are on the opposite side of the lens from
the object.
Diverging lenses create virtual/erect images that are on the same side as the object.

Basic Lens formula:
U+D=V
100/u (cm) + D = 100/v (cm)
U = vergence of object at the lens
u = object position = 100/U (cm)
D = lens power
V = vergence of image rays
v = image position = 100/V (cm)

Fnew = Fcurrent/(1-dFcurrent) where F is in Diopters and d is in meters.

The primary focal point (F1) of a lens is also called the Object-Space Focus.
For a plus lens, this is the point from which light must originate to emerge parallel from the
lens. Thus, the image is at infinity.
For a minus lens, this is the point towards which the incident light must be directed in order
for the image rays to emerge parallel.
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Secondary focal point (F2) of a lens is also called the Image-Space Focus.
For a plus lens, this is the point where parallel rays from a distant point object are rejoined
to form an image at that point. When parallel rays enter the optical surface, they will focus at
the secondary focal point.
For a minus lens, this is the point from which diverging rays seem to come from, after a
parallel bundle of rays are refracted by a negative lens.

The anterior focal point is approximately 17mm (1/-60 = -16.67mm in front of the cornea)
and the eye is 22.6mm in length with the nodal point 5.6mm behind the cornea.
The nodal point is the point in the eye where light entering or leaving the eye and passing
through the nodal point, is undeviated. This allows similar triangles to be used to determine
the retinal image size of an object in space. For example, to determine the retinal image size
of a Snellen letter (viewed at 6 meters), the following formula would be used: Retinal image
height/Snellen letter height = 17mm/6000mm
The far point of the eye is the object point imaged by the eye onto the retina in an
unaccommodated eye.
The near point of the eye is found when the uncorrected refractive error of the eye is added
to the accommodative ability of the eye. If the amplitude of accommodation is 10D, the near
point is 10cm in front of the eye (specifically, 10cm in front of the vertex of the cornea which
is used as a convenient reference point).

According to Knapp‘s Law, the retinal image size will not be different between the two
eyes, no matter what amount of axial ametropia exist, when the spectacle lens is placed at
the eye‘s anterior focal point.

The Amplitude of Accommodation, also known as the accommodative response, is the
maximum increase in diopter power obtainable by an eye. The amplitude of accommodation
is measured monocularly.

The Range of Accommodation denotes the linear distance (expressed in centimeters or
meters) over which the accommodative power allows an individual to maintain clear vision.
The range lies between the near point of accommodation and the far point of
accommodation.
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This is considered the most useful clinical measurement of accommodation.
It helps answer the question as to whether an individual‘s accommodative range comfortably
encompasses his visual needs.

When wearing contact lenses, the convergence requirement is the same as that of an
emmetrope, because the lenses rotate with the eye and the line of sight remains relatively
well directed through the center of the lenses.
As a myope converges to bi-fixate a near object, his line of sight departs from the center of
his spectacle lenses and encounters increasing amounts of base in prismatic effect. The
spectacle wearing hyperope encounters base out prismatic effect, as he converges to bifixate a near object. Thus, to bi-fixate a given object at a distance less than infinity, the
bespectacled myope converges less than the emmetrope or the contact lens wearer, while
the hyperope wearing spectacles converges more than the emmetrope or the contact lens
wearer. Therefore, the myope who discards his spectacle lenses in favor of contact lenses,
must converge more to bi-fixate a given near object, while the hyperope will converge less
under the same conditions.

Relative Distance Magnification = r/d where r = reference or original working distance and
d = new working distance
Relative Size Magnification = S2/S1 where S1 = original size and S2 = the new size
The ratio of the image size to the object size or image vergence to object vergence is called
transverse or linear magnification. MT = I/O=U/V = v/u

The power of a lens is an indication of how ―strongly‖ it refracts (bends) incoming light rays.
The power, P, is equal to one over the focal length in meters and has units of Diopters (D).
P (diopters) = 1/f (m)

The Airy's disc is a diffraction pattern when light passes through the edge of an
obstacle. It contains a bright central disc ie. Airy's disc that receives about 90% of the
luminous flux. This disc is surrounded by concentric light and dark rings. The radius of the
disc is proportional to the wavelength of the light but inversely proportional to the pupil size.
Sir George Airy, (1801–1892) Astronomer, was the first to calculate the energy distributions
in the pattern.
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Approximately 84% of the total energy of the diffraction pattern is in the Airy disc. The
remaining energy is distributed in the surrounding rings that become progressively fainte
Two object sources of light (S1 and S2) cannot be resolved if their diffraction patterns (Airy
discs) overlap substantially.
Rayleigh‘s criterion: central maxima of one diffraction pattern falls on the first minima of
the diffraction pattern from the second source, and the two images can just be resolved.

Polarimetry uses the birefringence of the NFL (nerve fibrelayer) to quantitate its thickness
indirectly. The change in the polarization of light as it passes through the NFL, or
―retardation,‖ is measured and linearly correlated to the NFL thickness.

Illuminance and irradiance are terms used to refer to the amount of light arriving at a given
point. Radiance refers to the amount of light leaving a certain point.

Catoptric images are images reflected from the surfaces of the eye. It is other name of
commonly known purkinje images.

To appreciate difference in stimuli, human eye requires 10% difference in stimuli.

The eye can accommodate in the absence of convergence. However, in normal daily life
a patient with normal binocular vision will convergence when he/she accommodates. The
normal ratio is 3:1 to 5:1.

The refractive index of a material is different for different wavelength and in general it
is usually measured with yellow sodium flame.

The frequency of a light does not change as it travels from one medium into another but the
wavelength become shorter.

The vergence power of a lens is affected by
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o
vergence power of each surface
o
thickness of the lens and
o
medium on either side of the lens.
Dhaval Patel MD
The later explain why cornea has a stronger refractive power than lens in human eye
although its refractive index is less. The wavelength of the light also affects the vergence
power of the lens.

The first focal length has the same length as the second focal length only if the media
on either side of the lens are the same.
The first focal length of a convex lens is to the left of the lens whereas that of the concave
lens is to the right of the lens.
By convention, the second focal length has a positive sign for convex lens and a negative
sign for concave lens. As lenses are designated by their second focal lengths, a convex
lens is also called a plus lens and a concave lens a negative lens.

Image magnification can be defined in various ways:
Linear magnification is the quotient of the image height divided by the object height.
Axial magnification is the magnification of the depth of the image along the optical axis.
Angular magnification is the quotient of the angle subtended by the image divided by the
angle subtended by the object.

Maddox rod is used to measure distant phoria and Maddox wing for near phoria. Double
Maddox rod can be used to measure cyclotorsion.

Spectacle cannot correct irregular astigmatism. It is treated by substituting a new surface
and this can be achieved with a contact lens usually RGP lens, corneal graft or laser
surgery.

Placed before an ametropic eye, the cross-cylinder does not alter the spherical
equivalent, but it will enlarge or contract the interval of Sturm, blurring or clarifying the
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image, as it increases or decreases the net astigmatic ametropia. The power of the
cylinder is twice that of the sphere and of opposite sign.

High-order aberrations are ones that cannot be corrected by simple spherocylindrical
systems, such as spectacles or contact lenses. They are caused by minute misalignments of
the eye's optical components and include, in order of visual significance, spherical
aberration, coma, higher-order astigmatism, and others. They can be detected with
wavefront analysis performed with an instrument called aberometer. Theoretically, an
ablation that removes aberrations increases visual contrast and the spatial detail of images
seen by the eye.

Anisometropia of more than 1D in hypermetropic patients can not be controlled with
unilateral accommodation because accommodation is a binocular process. Therefore the
image in one eye is often blurred and is a cause of amblyopia.

The image is moved forward when a correcting lens is moved forward irrespective if the
lens is concave or convex.

The accommodation is the sum of the patient's refractive state + 4D. For comfortable
near vision, one-third of accommodation should be kept in reserve.

The Franklin design is a split bifocal in which a distance lens is mounted on a near lens.
The cemented design involves attaching a supplementary lens to the surface of a distance
lens of the same refractive power.
Fused bifocal is made by heat-fusing a near portion made of flint glass into a depression on
a crown glass with a lower refractive index.

Varifocal glasses have three sections: distance, intermediate (for VDU or working at arm
length) and near (for reading).
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Dhaval Patel MD
Contact lens with the following numbers 8.9/13.8/-4.25: base curve/diameter/power
(BDP)

The radiuscope is the traditional instrument used by practitioners and laboratories to
measure the radius of spherical base curves.

Piggyback contact lens involves the use of two lense; the soft contact lens provides the
fitting surface for the rigid gas permeable lens.

Corneal warpage refers to change in the corneal curvature associated with contact lens
wear.
Corneal oedema is absent.
It is commoner with rigid gas permeable contact lens than soft contact lens.
The result is reversible. Biometry or refractive surgery should be avoided until the cornea
returns to its normal shape otherwise the results of the measurement or surgery will be
inaccurate.

Wollaston prism is used in the Javal-Schiøtz instrument to double the image formed by
reflection on the cornea.

Astigmatic keratotomy is placed perpendicular to the steepest meridian. Coupling is a
problem and it is defined as steepening of cornea at 90 degrees perpendicular to the
meridian that has been flattened by the incision though not to the same degree.

As neutrality is approached, the reflex becomes Faster, brighter and thinner. When the
refractive error is neutralized, the pupil is suddenly filled with light.

When the retinoscopy reveals +2.00-1.75 X 180 at working distance of 67cm, the final
refraction will be +0.50 -1.75 X 180. This cylinder portion of the correction is
unchanged.
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Dhaval Patel MD
2 basic methods of retinoscopy:
1. neutralize one meridian with sphere and the other with the cylinder If you are
working at a distance of 67cm, and you find that with the streak at 90 degrees +2.00
D sphere neutralized the reflex; with the streak at 180 degrees (with the sphere in
place) a -2.00D cylinder neutralizes the reflex. The patient's final refraction is +0.50 2.00 X180.
2. sphere to neutralize both axis With the streak at axis 90 degrees, a +3.00D lens
neutralizes the reflex. With the streak at axis 180 degrees, a +6.00D lens neutralize
the reflex. If the working distance is 67 cm, the final refraction is +4.50 -3.00 X 90.

Duochrome or binocular balance tests is not needed in aphakic, pseudophakic and
patients over 50 as they have no or little accommodation making the tests unnecessary.

Binocular balance procedure
o
In monocular refraction one aims to obtain the maximum positive correction with
the accommodation fully relaxed. However, if the eye not being examined
accommodates behind the cover, then the maximum correction will not be achieved.
Binocular balancing is a check for this small amount of accommodation.
o
Prism dissociation balance
o
With the patient binoculary viewing a block of letters at a 6 m distance

Remember to give maximum positive sphere equal to best visual acuity and minimum
negative sphere.

Cross compound lens: a combination of lens in which power of cylinder is more than
power of spherical lens with opposite signs.

Patient having mixed astigmatism may not complain of defective vision as the circle of
least diffusion falls on his retina and hence his visual acuity is very good even without
glasses.
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
A difference of 1D in refractive status of two eyes creates a difference of 2% in size of retinal
image of two eyes. Up to 5% difference in retinal image size of two eyes is well
tolerated. Thus an anisometropia of up to 2.5D is acceptable. Anisometropia of up to 4D
may be acceptable in some individuals and more than 4D creates diplopia.

Purkinje Images are also known as Catoptric imagery.
4 images: 1,2,3 are virtual and erect while 4th is real and inverted.
1,2 are near pupillary plane, 3rd is in the vitreous whereas 4th is in the lens.
Clinical Applications
1. To diagnose presence or absence of lens.
2. Keratometry makes use of first Purkinje image.
3. Type of cataract: In MSC and HMSC, Fourth Purkinje image is absent.
4. Hirschberg test: First Purkinje image is used for estimation of angle of squint.

Remember that while checking a lens if its convex or concave, if image seen by it moves in
same direction, then its concave lens which is used in myopia. Don‘t confuse this with
refraction in which reflex moves in opposite if its myopia >1.5D.
Concave mirror converges parallel rays of light and convex mirror diverges parallel rays of
light. This is in contrast to concave lens which diverges parallel rays of light and convex
lens which converges parallel rays of light.

Reflex convergence is of four types: FAT-P
1. Proximal convergence: Psychological awareness of a near object initiates this type of
convergence.
2. Tonic: It means that when the patient is awake there is an inherent tone in the
extraocular muscles.
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3. Fusional: It is initiated by a bi-temporal retinal image disparity and is not associated with
change in refractive status of eyeball. It ensures that image of an object falls on
corresponding retinal points in the two eyes.
4. Accommodative: It is initiated by act of accommodation. It means that when we
accommodate; we converge. It is a part of near reflex. One dioptre of accommodation is
accompanied by 4-5 prism diopters of accommodative convergence and it remains fairly
constant. Abnormalities of accommodative convergence are associated with squint.

Speed of light is the fastest anything has been observed to move. In vacuum, the
speed is three lakh kilometers per second or one lakh eighty six thousand miles per
second. At this speed, it takes light one ten thousandth of a second to travel around the
earth.

The angle of incidence, for which angle of refraction is 90° is known as critical angle.
For example, fibre-optic cables, gonioprisms, diamond shining at night.

A sound wave, by contrast, vibrates back and forth along its propagation direction and thus
is not polarizable.

LAW OF INVERSE SQUARE:

o
applies to light, sound, electricity, gravitation
o
It states that the intensity of light, i.e. luminance radiating from a point source is
inversely proportional to the square of the distance from the source.
o
E = 1/d
2

E = Energy at one particular point

d = Distance of point from the source of light
Positive angle kappa represents a slight temporal position of the fovea relative to the
optical axis. This causes a slight temporal rotation of the globe to keep the image on the
fovea. This, in turn, causes the corneal light reflex to be displaced nasally. The deviated light
reflex remains stable with cover testing as the fovea never spontaneously moves relative to
the optical axis
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
Centrad is that strength of a prism which produces a deviation of 1 cm of arc at a
distance of 1 meter. It is old unit and no more in routine use now.

How to Detect and Measure Strength of a Prism
o
Manual Method: See a straight line through a prism. It appears broken. Line
appears to be deviated towards its apex. Now place a prism of known strength in
such a way that base is towards apex of test prism. When prism of correct power is
chosen, straight line appears unbroken again.
o
With Lensometer: Place a prism on the platform. Look through eyepiece of
lensometer. The green target appears deviated. Now combine a prism of known
power with prism of unknown power placed apex to base. Place this combination on
the platform and see through the lensometer. The target has moved towards the
center.
o
Another Method: Check prism by using the Prism Reference Point (PRP), also
called the Prism Compensation device in the lensometer by noting the displacement
of the mires from the central ring of the PRP. Each ring is marked with a number, the
center is zero. Each ring represents one diopter of prism. If the mires are located two
rings from the center, the prescription contains 2 diopters of prism.

In PST (photostress recovery test), Patients who have a maculopathy will take longer (90 to
180 seconds) to recover pretest vision after looking into a bright light for 10 seconds.
Patients with optic nerve disease will have a normal recovery time (<60 seconds). The test
is probably only valid for patients with vision better than 20/80.

A pattern VER (as opposed to a flash VER) is required for visual acuity assessment in
preverbal children.

In patients with macular disease VA is frequently worse when the patient looks through a
pin-hole.

A lens is a transparent medium bound by two surfaces which are part of spheres.
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A mirror is a part of a hollow sphere whose one side is polished.

Aspheric Lens and Achromatic Lens
o
Aspheric or aplanatic glasses are grinded in such a way that their curvature (and
hence power) is maximum in the center and gradually decreases towards periphery.
Thus an aspheric lens of +10 DS has a power of +10 DS at the center and +6 DS at
the extreme periphery
o
An achromatic lens can be manufactured by combining two glasses of different
dispersive power and different refractive index. Flint glass has a refractive index of
1.65 but dispersive power double than that of crown glass. Ref. index of crown glass
is 1.5. Thus if a + 2.00 DS lens of crown glass with +2d dispersive power is
combined with –1.00 DS lens of flint glass which has –2d dispersive power, a +1.00
DS lens with zero dispersive power is obtained

Maximum resolving power of human retina (smallest distance between cones) = 20
seconds of arc

Accommodative insufficiency is associated with systemic processes such as
hypothyroidism, anemia, pregnancy, nutritional deficiencies, and chronic illness.

Aberrations of Thick lenses: CCODS
1. Spherical aberration:
2. Coma:
3. Astigmatism of oblique incidence:
4. Chromatic aberration:
5. Distortion:

The reciprocal of the best Snellen acuity is equal to the plus power of the lens required.
For example, if a patient can read 20/60, a +3.00 D will suffice. The reciprocal of the diopter
power gives the reading distance (i.e., 33 cm).
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
Geneva lens clock: A device to determine the base curve of the back surface of a
spectacle. It is often used clinically to detect plus cylinder spectacle lenses in a patient
used to minus cylinder lenses. It is specifically calibrated for the refractive index of crown
glass. A special lens clock is available for plastic lenses.

Snell's law (law of refraction) = the incident and refracted rays and the normal to the
surface at the point of incidence lie in the same plane and the ratio of the sine of the angle
of incidence i to the sine of the angle of refraction r is a constant for any two media. This
constant is called the relative index of refraction ie.
sin i / sin r = refractive index

Apex angle in degrees of a 10 dioptres prism is 10 degrees.

The nodal point of a lens is at the intersection between the principal axis and the principal
plane.

The image produced by a negative lens is virtual, erect and diminished.

A focimeter measures the back vertex power of a lens.

A decentration of 10 mm from the optical centre of a +5 dioptre lens produces a prismatic
effect of 5 prism dioptres

A X8 loupe has an equivalent power of 32 dioptres.

In trifocals the intermediate lens usually has an addition of 1 dioptre over the distance
correction or half of near add.

The LTF stands for luminance transmission factor when considering tints.
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
Relative spectacle magnification = Actual size corrected with spectacle/size seen by the
emmetropic eye

0.50 Jackson cross cylinder: +0.50DS/-1.00DC at 135

Lister‘s bulb: in retinoscopy with Pristley Smith mirror

Porro–Abbe prism: type of reflection prism used in some optical instruments to alter the
orientation of an image. It is made from a piece of glass shaped like four right-angled
reflecting prisms joined face-to-face in a twisted fashion. Light enters one flat face, is
internally reflected four times from the sloping faces of the prism, and exits the second flat
face offset from, but in the same direction as the entrance beam.

Antireflective coatings use destructive interference.

Total hyperopia = manifest hyperopia (absolute hyperopia + facultative hyperopia) +
latent hyperopia. T=MAFL
Manifest: Both part of hyperopia that can and cannot be corrected by the power of
accommodation
Absolute: That part of hyperopia that cannot be corrected by the power of accommodation
Facultative: That part of hyperopia that can be corrected by the power of accommodation
Latent: That part of hyperopia that can be corrected by the tone of ciliary muscle

In DO, the optic disc may not be focused as you see it, as hypermetropic patients require
more ―plus‖ (green numbers) lenses for clear focus of the fundus while myopia patients
require more ―minus‖ (red numbers).

Direct Ophthalmoscope provides linear magnification of 1x.
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15x is an angular magnification of Direct Ophthalmoscope.

It has generally accepted that 0.25 diopter difference of refraction causes 0.5% differences
in image size.

Six meters is accepted from practical point of view because most rays from a distance of 6
meter and more are as good as parallel rays.

The angle of minimum deviation is produced by a prism when light undergoes equal
bending at the two faces. When light strikes the prism perpendicular to one of its surfaces
(Prentice position), the angle of deviation is greater.

Glass prisms are usually calibrated in the Prentice position, in which one face is
perpendicular to the incident light.
Plastic prisms and prism bars are usually calibrated with the angle of minimum deviation
Frontal position. When measuring strabismus with glass prisms, they must be held in this
position to be accurate; that is, glass prisms must be held with one surface perpendicular to
the visual axis. Real images are deviated toward the prism base. Virtual images are
deviated toward the apex.

The absolute value of the back vertex power of a meniscus spectacle lens is always
greater than that of the front vertex power. Because the focal length measured from the
―rear‖ vertex of a meniscus lens is always shorter than the corresponding ―front‖ focal length,
the absolute value of the back vertex power (P = n/f, where n = 1 in air) is always greater
than that of the front vertex power. The true power is somewhere between the two.

The flatter (not steeper) peripheral cornea tends to counteract spherical aberration.
The total interval of chromatic aberration in the human eye is approximately 1.25D. Tilting a
lens along its horizontal axis induces cylinder of the same (not opposite) sign and along the
same axis, as well as sphere of the same sign. Shorter wavelengths of light are refracted
more than longer wavelengths. When polychromatic light is focused on the retina (as is the
case in emmetropia or proper spectacle correction), blue light is 0.87D anterior to the retina,
green light is 0.37D anterior to the retina, and red light is 0.37D posterior to the retina.
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
A Maddox line produces two line images of a point light source: a real image that is too
close to the eye to be seen, as well as a virtual image running through the light source. The
real image is parallel to the cylinders' axes, whereas the virtual image is perpendicular. This
is true for all spherocylindrical lenses (even those with no power in one meridian).

The angular size of the field of view for an observer looking at a plane mirror is independent
of the observer's position.

Hyperacuity is of two types: Stereoacuity and vernier acuity.
Vernier acuity refers to the ability of a normal human eye to discriminate between two line
segments in the frontal plane separated by as little as 8 seconds of arc (one third the
diameter of a cone). Determination of accurate end points with the keratometer,
lensometer, and applanation tonometer relies on this degree of spatial discrimination.
Normal Stereo Acuity is 10-60 seconds of arc.

Conjugate planes are related by being the object and image of one another.

The binocular amplitude of accommodation usually exceeds the monocular amplitude of
accommodation.

Accommodative amplitude decreases with age with the following approximations:
1. Accommodative amplitude at age 40 = 6.0D, at age 44 = 4.5D, and at age 48 = 3.0D.
2. Below age 40, accommodative amplitude increases by 1.0D for every 4 years.
3. Above age 48, accommodative amplitude decreases by 0.5D for every 4 years.

Cylindrical lenses produce minor monocular distortions caused by differential meridional
magnification, which may produce intolerable binocular spatial distortions. The sources of
differential meridional magnification can be minimized by:
1. Prescribing in minus cylinder form.
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2. Minimizing vertex distance.
3. Decreasing cylinder power (while maintaining the proper spherical equivalent).
4. Rotating the axis of the correcting cylinder toward 90 or 180 degrees.

Most distortions of aphakic spectacle lenses stem from their position anterior to the pupil
and include image magnification, ring scotoma, pincushion distortion, and the so-called jackin-the-box phenomenon. Aphakic spectacle lenses can also create cosmetic problems not
only because of their size but also because they can make the patient's eyes look
magnified.

The magnification associated with any corrective lens diminishes as the lens
approaches the eye's nodal point.

o
IOL decreases image magnification to <4%
o
20% to 30% with aphakic spectacle correction
o
7% to 12% with aphakic contact lens correction.
At the correct axis, the following are true:
1. The break phenomenon disappears (the intercept and reflex are parallel).
2. The width of the streak is narrowest.
3. The intensity is brightest.
4. Skew motion is no longer observed.
Intensity and skew are primarily useful for small astigmatic errors, while break and
width are best judged with an enhanced streak. Astigmatic errors of <1.0D do not
enhance well, so break and width are not readily appreciable.

The spherical equivalent is discovered by fogging the eye (adding a lot of plus sphere) to
relax accommodation, then adding minus sphere until vision is sharpest. At this point, the
circle of least confusion is on the retina. Then, the cross-cylinder is introduced to find axis
and power. The circle of least confusion must remain on the retina throughout cross-cylinder
testing. When fogged, the circle of least confusion is anterior to the retina.
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The sphere end point can be verified by the duochrome test, but this test does not relax
accommodation. Therefore, the test should be introduced with the patient slightly fogged,
such that the letters on the red side are clearer (the red letters will focus behind the green
letters, closer to the retina). Then, minus sphere is added until letters on the green and red
sides are equally clear.
An emmetropic person sees red and green colors equally sharp. After giving correction
patient is asked to read FRIEND. FIN letters are written in green and RED letters are written
in red color. If myopia is over corrected or hypermetropia is under corrected patient will
appreciate green letters much better than red letters. On the other hand if myopia is under
corrected or hypermetropia is over corrected patient will appreciate red color much better.
Or simply you can remember,
If RED clear, add MINUS
If GREEN clear, add PLUS.

Image jump can occur in any correction whose add does not have its optical center at the
top of the segment. Round-top segments typically produce more image jump than flattop segments, as they have much lower optical centers.
Image displacement occurs in all corrections as gaze moves away from the optical center
of the correcting lens; this is unlikely to be significantly distressing unless an imbalanced
displacement occurs, as in anisometropia. The other situation where image displacement is
troublesome is when an increased demand is made on already taxed vertical fusional
system ability, as in compensated vertical phoria.

Holding the radius of curvature constant, larger diameter lenses are effectively steeper.
At a given diameter, radius of curvature and lens steepness is inversely proportional.

If the center of curvature of the refracting surface is on the same side as the medium of
higher index of refraction, the surface is positive, regardless of direction of light
propagation.
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Candela is the unit of measure of luminous intensity, which is defined as the light emitted
per unit of solid angle.
Luminous flux is the quantity of light leaving a source or passing through a region of space,
and it is measured in lumens.
Illuminance is the quantity of light per unit area incident on a surface or at an image, and it
is measured in lux.
Luminance is the light reflected or emitted by a surface per unit area and per unit solid
angle, and it is measured in apostilbs.

Why vision is 6/6?
Two points discriminable as long as they stimulate two separate cones.
Width of a foveal cone = 2.5u (30sec angular separation)
Individual part of 6/6 letter = 1 min angle at fovea
In order to properly represent the peaks and troughs in the intensity profile of a sinewave,
there must be at least two cones for each cycle of the grating. This is known as the Nyquist
limit.

Types of Visual Acuity

Minimum visible: Best threshold is 1 sec arc

Minimum resolvable/recognizable: Best threshold 30 sec arc

Minimum discriminable(hyperacuity): Best threshold is 2 sec arc

optical correction of presbyopia can also be achieved with hyperopic [orthokeratology]
lenses, bringing the advantages of waking hour visual correction without the need for
glasses or contact lenses to a rapidly growing sector of the optical market.

MRI Prism Glasses: Non-Magnetic Prism Glasses allow the patient to see the room outside
the bore of magnet during their scan, allowing a companion or scenic picture to be viewed.
A simple and cost effective comfort measure to be used alone, or in conjunction with a
sound system for ultimate relaxation in an MR environment. Also known as recumbent
spectacles.
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
The development of presbyopia is independent of ocular parasympathetic nerve paresis.

Visual acuity is usually better in blue cone monochromatism than rod monochromatism.

Becker's test: A test for astigmatism that uses diagrams of sets of three lines radiating in
different meridians.

Retina is most sensitive to yellow light in photopic conditions. In scotopic conditions it is
most sensitive to blue light.

The Sloan Letters: 10 letters C, D, H, K, N, O, R, S, V, Z

X notation for magnification:

o
Multiply the amount of magnification by 4 to get the ―Dioptric Power‖ of the lens.
Divide the Dioptric power into the number 40 to get the number of inches from the
eye.
o
For example, a 4X lens is 16 Diopters. Divide into 40, we get a 2.5" working
distance; a 5X lens is 20 Diopters and has a reading distance of 2 inches
Aspheric lenses are lenses which have a relatively flat surface, yet still offer the same
vision quality as non aspheric lenses. This is because although the lens is thinner and
flatter, it still refracts light to exactly the same degree as a conventional lens.
Double aspheric lenses are essentially an even better version of the already useful
aspheric lenses. Not only is the front of the lens aspheric, but the back of the lens has
the same aspheric design, hence the name, ‗double aspheric‘. Typically, when you look
out from the edge of your lenses, the image you see can be distorted. Double aspheric
lenses limit this distortion of image right up to the edges of the lens. This is done by
ensuring that a large area of the lens is the focal point.

Photoreceptors:
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o
"red" cones (64%), "green" cones (32%), and "blue" cones (2%)
o
The green and red cones are concentrated in the fovea centralis.
o
The "blue" cones have the highest sensitivity and are mostly found outside the
fovea, leading to some distinctions in the eye's blue perception.
o
The cones are less sensitive to light than the rods
o
visual acuity or visual resolution is much better with the cones, the rods are better
motion sensors
o
Rods Do Not See Red!  The light response of the rods peaks sharply in the blue;
they respond very little to red light.

The ship captain has red instrument lights. Since the rods do not respond to
red, the captain can gain full dark-adapted vision with the rods with which to
watch for icebergs and other obstacles outside.

Dispersion is the variation of refractive index with wavelength. In general, the shorter the
wavelength, the higher the refractive index. For instance, in spectacle crown glass, light of
wavelength 656 nm (corresponding to red) has an index of 1.520, whereas light of
wavelength 480 nm (corresponding to blue) has an index of 1.531. In the crown glass
example, the dispersion is 0.011 (= 1.531 - 1.520).

Light scattering:

o
If light strikes a structure larger than 1000 nm, the light is absorbed.
o
If the structure is less than 1 nm, the light passes by unaffected.
o
However, if the object has a size between 1 and 1000 nm, light will be absorbed
and re-emitted as a ray of similar wavelength, but in a different direction.
Magnesium fluoride (MgF2), a durable substance with an index of 1.38 at 550 nm, is the
most commonly used coating material for single-layer antireflection coatings. Instead of
one reflection at the air-glass interface, there is now a reflection at the air-MgF2 interface
and a second reflection at the MgF2-glass interface. These reflections interfere
destructively, resulting in a minimum reflectance within the visible spectrum (at normal
incidence) of 1.5% or less, as compared with the original 4% for the uncoated glass surface
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
The rods have peak sensitivity at 500 nm that corresponds to blue-green, and the foveal
cones have peak sensitivity at 562 nm or in yellow-green. The significance of this shift in
sensitivity is that the foveal cones respond more strongly to longer wavelengths where
chromatic aberration gradually increases, whereas rods respond more strongly to the region
of rapidly increasing chromatic aberration.

When a glassblower or other glass worker heats glass directly in a flame, the flame
surrounding the glass emits a yellow light termed sodium flare.
Didymium or neodymium glass absorbs this light, which is emitted at approximately 589
nm, making it easier for the glass worker to view his or her work.

Most common mirror coating materials are chromium, aluminum, and copper.

Laser light is mainly absorbed in ocular tissue by three pigments

o
Melanin strongly absorbs all ultraviolet and invisible wavelengths. However, this
absorption by melanin decreases with increasing wavelengths.
o
Hemoglobin has strong absorption in the violet (420 nm) and green (514 nm)
wavelength. Deoxygenated hemoglobin absorbs red more strongly than does
oxyhemoglobin.
o
Xanthophyll which is the pigment most densely distributed in the macular area,
absorbs the blue wavelength (460 nm).
Factors that modify color perception
o
Brightness (bezold-brücke phenomenon): As brightness increases, most hues
appear to change. At low intensities, blue green, green, and yellow green appear
greener than they do at high intensities, which make them appear bluer. At low
intensities, reds and oranges appear redder, and at high intensities, they appear
yellower. The exceptions are a blue of about 478 nm, a green of about 503 nm,
and a yellow of about 578 nm. These are the wavelengths of invariant hue.
o
Saturation (abney effect): As white is added to a hue, the hue appears to change
slightly in color. The effect is similar to adding yellow. Blue greens become
greener and yellow greens become yellower. Reds and oranges also become
yellower. The exception is a yellow of 570 nm.
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State of dark adaptation (purkinje effect): The relative luminosity curve illustrates
the eye's sensitivity to different wavelengths of light. When the eye is light adapted
(daytime), yellow, yellow green, and orange appear brighter than do blues, greens,
and reds. The cones' peak sensitivity is to light of 555 nm. A relative luminosity
curve can also be constructed for the rods in a dark-adapted eye. The lights are so
dim that the observer cannot name the various wavelengths used. Rods are most
sensitive to light of 505 nm (blue). It has been postulated that rods share the
pathways used by blue cones. As the eye dark adapts and rods begin to send
messages, more blue messages are sent to the hue center. Therefore, at dusk,
although the brightness of all colors decreases, blues and greens appear to gain in
relative brightness when compared with yellows and reds. This phenomenon is
called the Purkinje effect after the Czechoslovakian scientist Purkinje, who first
described it while watching blue and green flowers become relatively brighter (as
compared with red and yellow) at dusk.

Power of air filled eye: (-150) D

Eigengrau: (―dark light,‖ retinal ―self-light‖): Complete dark adaptation of the eye does
not produce a sensation of absolute black. Instead, a uniform gray with superimposed
phosphene-like dots is generally noted. The dots observed in this entoptic phenomenan
are more mobile than phosphenes and may form colored patterns that drift about the field.

Troxler fading
o
refers to the spontaneous suppression of the visibility of an image that occurs
when one stares intently at a point in a scene. After some seconds or even minutes,
parts (but not all) of the field will lose contrast and merge into a misty blur. Moving
the eyes restores clear vision.
o
Ignaz Paul Vital Troxler 1804
o
E.g: Lilac chasec (card with disappearing dots)

Haag-streit slit lamp decreases binocular viewing angle from 13.5 degrees to 4.5 degrees.

Cornea absorbs rays shorter than 295 nm. Therefore rays between 600 and 295 nm only
can reach the crystalline lens.
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The normal human eye is insensitive to wavelengths between 400 and 350 nm (ultraviolet
rays) because they are absorbed by the crystalline lens of the eye.
In aphakic eyes the light rays between 350 and 400 nm can also pass on the retina.
Therefore, the Aphakic eyes are sensitivc to those wavelengths which give rise to the
sensation of blue or violet colour so the newly aphakic patients often complain that every
thing looks bluer than visualized before the operation.

Persistence of the eye is 0.1 second: i.e. if the time interval between two successive light
pulses is lesser than 0.1 second, eye cannot distinguish them separately

Raman Effect: The light (or photons) impinging on a molecule interacts in various ways but
the final outcome always results in the scattering of light. For example, we do not see light
directly. We always see light and objects as a result of scattered light. Scattering is
absorbance of incident light used in exciting the atom and reradiation of this light. The
Raman scattering is the result of inelastic collisions in which the scattered photons
exchange energy with the vibrational energy modes of an atom.

In a toric surface, one principal meridian is more curved than the second principal
meridian. The principal meridian with minimum curvature, and therefore with minimum
power, is called base curve of a toric lens.

A reduction of 1 mm in the depth of the anterior chamber (through a forward shift of the
crystalline lens) would increase the eye's total power by about 1.4 D.

Accommodation in uncorrected myopes is not developed normally. Since they need
not accommodate to see the near objects clearly. For this reason they may suffer from
convergence insufficiency, exophoria and early presbyopia as they grow older.

Night myopia or twilight myopia: The shift from photopic to scotopic vision at twilight is
associated with increased sensitivity to the shorter wavelengths of light. The
emmetropic eye, if accommodated for the middle range of the visual spectrum, will be
slightly myopic for the shorter wavelengths.
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
Symmetric astigmatism: refers to the regular astigmatism in which the principal meridia in
each eye have similar but opposite axes, e.g. 15° in left eye and 165° in right eye which
together add up to 180 +- 15°.

Depth of field: the range of distance from the eye in which an object appears clear without
change of accommodation.

Depth of Focus: The range at the retina in which an optical image may move without
impairment of clarity is termed as depth of focus.

Reaction time:
Accommodation: Far to near: 0.64 s
Accommodation: Near to Far: 0.56 s
Direct light reflex: 0.26 s
Convergence response: 0.2 s

Causes of premature presbyopia
o
Uncorrected hypermetropia
o
Premature sclerosis of the crystalline lens
o
General debility causing presenile weakness of ciliary muscle
o
Chronic simple glaucoma

Angle of convergence becomes smaller with increasing fixation distance and becomes
larger with increasing IPD.

In air, the speed of light remains relatively constant. When the light passes through a
higher index of refraction, its properties change and aberrations are formed. This can be
explained by the following equation:
F = Vn/ λ
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F = frequency, V = velocity, n = index of refraction, λ = wavelength.

The waves of light are joined at a single point in time by what is called a wavefront and
always travel perpendicular to it. The distorted shape that a wavefront takes after emerging
from an irregular optical media is called a wavefront aberration.

A practical example of spherical aberration is the comparison between the optical
properties of the +20D trial frame lens and the aspheric indirect binocular
ophthalmoscope (IBO) +20D lens. Both lenses focus light coming from infinity to a focal
point of 5 centimeters behind the lens. However, when analyzing the quality of the entire
image, one can observe a deformity in the periphery of the image formed by the trial frame
lens, which is not present with the aspheric lens. The higher the power of a lens, the more
the distortion produced by spherical aberration.

Point spread function (PSF) is the intensity with which an optical system distributes
an image from a point source onto the retina. The point source is influenced by the pupil
size. The larger the pupil, the more irregular the shape of the point source imaged on the
retina

Modulation transfer function (MTF): MTF is the ability of the eye's optics to focus a
sharp image on the retina with high contrast. As light passes through optical structures of
the eye, it undergoes a process of ―degradation‖ which can be measured by MTF.

Optical limitations to vision
• Pupil size
• Nyquist sampling limit: The spatial frequency of the images entering the eye can be
influenced by the pupil size – the wider the pupil, the higher the spatial frequency of an
object that can be perceived by the eye. However, the highest spatial frequency that can
be detected by the visual system is also limited by the number of photoreceptors densely
packed in the fovea also known as the Nyquist Sampling Limit.
• Diffraction: a phenomenon which occurs when light waves are bent as they enter an
aperture – in the case of the human eye, the pupil. In 1896, the German physicist,
Arnold Sommerfeld, defined diffraction as ―any deviation of light rays from a rectilinear
path which cannot be interpreted as a reflection or refraction‖.
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• Styles-Crawford effect: This is the effect of light entering the cones transversely
from the pupil margin, which is perceived half as bright as the light entering the center of
the pupil. In simpler terms, light that passes through the edge of the pupil contributes
less to image quality than light entering the center of the pupil.

There are two classes of aberrations: chromatic and monochromatic. Theoretically,
correcting both chromatic and monochromatic aberrations increases the contrast of images
focused on the retina (contrast sensitivity).
o
o
Chromatic aberrations

also known as ―achromatism‖

inability of a lens to focus all colors of light on a single point.

arises because the index of refraction of the media is not the same for all
wavelengths.
Monochromatic aberrations

defects of an image caused by the nature of a lens

Types:
1. Piston
2. Tilt
3. Defocus
4. Spherical aberration
5. Coma
6. Astigmatism

Wavefront sensing devices
1. Shack–Hartmann
2. Tscherning aberrometer
3. Laser ray tracing
4. Slit skiascopy
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
The main focus of laser refractive surgery nowadays is to not only correct refractive errors
such as defocus and astigmatism, but to create customized ablations which compensate for
induced higher-order aberrations (HOA) such as spherical aberration (optimized ablation)
and also correct pre-existing aberrations (customized ablation).

Visual effects of aberrations
o
Glare
o
Starbursts
o
Haloes
o
Ghost images
o
Poor image contrast
o
Poor night vision

The term ―aberrometry‖ is used to describe the science of the detection and analysis of
wavefront aberrations.

optical path length (OPL) is defined by the number of oscillations of these light waves from
a point source of light, traveling through a media of x index of refraction at any given length.

The tear film contributes to up to 70% to the corneal refractive power. Dry eyes, for
example, have greater coma and spherical aberrations compared to non-dry eyes.

With an increasing market and demand for super sharp vision (i.e. ―super-vision‖), scientists
have worked hard at making this technology clinically available in many different forms.
There are two types of wavefront customized ablations: wavefront guided ablations
(WGA) and wavefront optimized ablations (WOA).
o
Both types of treatment aim to correct for HOAs in the eye. In WGA, the treatment is
aimed to correct the pre-operative HOAs, while in WOA, the treatment attempts to
reduce HOAs generated during surgery. The WOA profile corrects expected HOAs
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for an average eye, and those that are anticipated as a result of the surgery. This
means that an eye with higher than normal HOAs, will end up with near equally high
HOAs after treatment in WOA.
o
Excimer lasers used to treat wavefront-customized ablations typically use a smalldiameter and circular flying spot laser.
o
Ophthonix, Inc. (Vista, CA), has designed a lens available for commercial use,
which consists of a three-layer structure with a refractive index of 1.6. The middle
layer consists of a patented photo-polymer in between two coated lenses. The lens
corrects HOAs from the 2nd to 6th order using wavefront guided technology.
The company's aberrometer measures both lower- and higher-order aberrations
using the ―Talbot‖ effect.
o
To compensate for positive spherical aberration, aspheric IOLs were designed and
are commercially available, such as the Tecnis-Z9000 (Pfizer, New York, NY) and
SN60WF (Alcon, Fort Worth, TX). These lenses are designed with a prolate anterior
surface, hence the term aspheric, and have the same radius of curvature at every
point on the surface.

Larsen noted that the axial length of the neonate's eye was 17 mm and that it increases 25
percent by the time the child reaches adolescence.

Neonate's visual appreciation for fine detail at birth is one-thirtieth (2/60) or approximately 3
percent & by the age of 12 months, the infant's level of visual acuity is 25 percent (20/80).

Most cases of myopia have an elongated eye. The stretching and weakening of the
sclera seems to depend on two major factors.

o
First, that the intraocular pressure maintains a constant force on the sclera.
o
Second, there is digestion of sclera architecture (collagen I fibers and extracellular
matrix) by metalloproteinase enzymes.
The coordination of the power of the cornea, crystalline lens, and axial length to process a
sharp retinal image of a distant object is known as emmetropization.
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
The cornea, which averages 48 diopters of power at birth and has an increased
elasticity, loses about 4 diopters by the time the child is 2 years of age. One may assume
that the spurt in growth of the sagittal diameter of the globe during this period pulls the
cornea into a flatter curvature. The fact that the average corneal diameter is 8.5 mm at 34
weeks of gestation, 9 mm at 36 weeks, 9.5 mm at term, and about 11 mm in the adult eye
supports this ―pulling, flattening‖ hypothesis.

The crystalline lens, which averages 45 diopters during infancy, loses about 20 diopters
of power by age 6 years. To compensate for this loss of lens power, the axial length
increases by 5–6 mm in that same time frame. (In general, 1 mm of change in axial length
correlates with a 3-diopter change in refractive power of the eye.)

Specifically, the size of the retinal image depends on an entity known as the nodal
distance, which averages 11.7 mm in the newborn and 16.7 mm in the adult emmetropic
schematic eye, giving a ratio of adult to infant retinal images of 1.43.

A partial list of giants of physiologic optics who have created schematic or reduced eyes
includes Listing, Helmholtz, Wüllner, Tserning, Matthiessen, Gullstrand, Legrand,
Ivanoff, and Emsley.

Significant amount of astigmatism develops in 56 percent of the infants. The transient
astigmatism just described tends to elongate tiny dots of the retinal image into lines. In
essence, these create the equivalent of a line drawing of the retinal image.

Line orientation receptors
o
In many infants the amount of astigmatism can rise to a level of greater than 2
diopters in the first year of life. The orientation of the distortion is usually horizontal
(180 degrees) initially. In the course of the next 2 years, the meridian of distortion
rotates to the vertical and the amount of the astigmatism diminishes. This slow
rotation of the axis of exaggeration can help activate different groups of brain
cells, which become sensitive to features in the retinal image with different tilts.
o
Drs. Hubel and Wiesel were awarded the Nobel Prize for Medicine in 1981.
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Role of the cornea
o
most powerful focusing element
o
Miller & Benedek proved that if the spaces consisting of glycosaminoglycan and the
size of the collagen fibers were smaller than one-half a wavelength of visible light,
the cornea is clear, even if the fibers were arranged randomly. An orderly
arrangement of the fibers also helps maintain corneal transparency.
Role of the crystalline lens
o
50 percent protein solution is cloudy
o
large protein molecules known as crystallins (large protein molecules ranging in
size from 45 to 2000 kD) seem to repel each other

Because the index of refraction of water is greater than air, objects underwater appear about
one-third closer and thus one-third larger than they would in air (i.e. magnification = 1.33×)

The act of accommodation is fast, taking only about one-third of a second.

Parenthetically, the cornea of many birds, from pigeons to hawks, can change shape to
accommodate. The avian cornea does not change flexibility with age; therefore these
birds do not become presbyopic. However, there is no ―free lunch‖ in nature. The human
lens, sitting within the eye surrounded by protective fluid is far less vulnerable to injury than
the cornea.

Role of the retina
o
The bird retina does not have blood vessels. The human retina has retinal blood
vessels that cover some of the retinal receptors and produce fine angioscotomas. A
bird's retina obtains much of its oxygen and nutritive supply from a tangle of blood
vessels (the pectin), which is covered with black pigment and sits in the vitreous in
front of the retina and above the macula (so as to function as a visor).
o
Probably the earliest chemical relative of rhodopsin is to be found in a primitive
purple-colored bacteria called Holobacterium halobium. Only one quanta (the
smallest possible amount of light) of visible light is needed to trigger the molecule.
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o
The fovea itself subtends an arc of about 0.3 degree.
o
distance between the centers of these tightly packed cones is about 2 µm. The cone
diameters themselves measure about 1.5 µm (a dimension comparable to three
wavelengths of green light) and are separated by about 0.5 µm.
o
One minute of arc is the spacing between the bars of a 20/20 symbol. Interestingly,
the sizing of the symbol was originally determined empirically.

chart luminance between 80 and 320 cd/m2 meet such criteria (160 cd/m2 is a favorite
level of illumination).

Clean printed charts using black characters on a white background usually have a
character-to-background luminance contrast ratio between 1/20 and 1/33.
For projected charts, the contrast ratio drops to a range of 1/5 to 1/10.

A patient happy with his or her vision but with visual acuity worse than 20/20 has been
described as a ―20/happy‖ patient. With physical evaluation alone it may not be possible to
diagnose such ―happiness,‖ but subjective tests such as a quality of life questionnaire may
help identify it.

Contrast may be considered as the difference in the luminance of a target against the
background:
photometer to measure the luminance of a target against the background. For example, a
background of 100 units of light and a target of 50 units of light yields the following.
A young, healthy subject may have a contrast threshold of 1 percent, or 1/100 (i.e. a
contrast sensitivity of 100)
In the visual psychology literature, the contrast threshold is described in logarithmic terms.
Therefore a contrast sensitivity of 10 is 1, a contrast sensitivity of 100 is 2, and a contrast
sensitivity of 1000 is 3.

When a transparent structure loses its clarity, the physicist describes it as a light scatterer
rather than a light transmitter.
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o
The word opaqueness conjures up the image of a cement wall that stops light.
o
most cataracts scatter light rather than stop light, the most graphic involves the
science of holography.
o
LeClaire et al observed that many patients with cataracts showed good visual acuity
but had poor contrast sensitivity in the face of a glare source.
o
first clinical glare tester – the Miller–Nadler glare tester:
Clinical conditions affecting glare and contrast sensitivity
o
Corneal edema: The stroma may increase in thickness by up to 30 percent before
the epithelium becomes edematous.
o
Patients with significant corneal astigmatism who wear thin soft contact lenses
experience blur that affects their contrast sensitivity.
o
Contrast sensitivity or glare testing may also be useful in detecting the earliest signs
of graft rejection.

The lens of a typical 20-year-old absorbs about 30 percent of incident blue light. At age
60, the typical lens absorbs about 60 percent of incident blue light.

a yellow pigment effectively absorbs or scatters away most of these harmful
wavelengths, thus diminishing the potential damage to the macula.

Vernier acuity: there is a visual task (Vernier acuity), which has a threshold of about 5
seconds of arc (1/12th of a minute of arc)

Some human studies have shown that use of atropine drops in children partially inhibits
the development of myopia.
Human use of topical pirenzepine was reported in two studies which showed a small but
statistically significant reduction in myopia and axial length.
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
Tyndall effect, also known as Tyndall scattering, longer-wavelength light is more
transmitted while the shorter-wavelength light is more reflected via scattering.

Rayleigh scattering, in that the intensity of the scattered light depends on the fourth power
of the frequency, so blue light is scattered much more strongly than red light

A lens free from distortion exhibits orthoscopy (or no distortion). The excess minification in
the periphery of minus lenses generally produces barrel distortion, while the excess
magnification of plus lenses generally produces pin-cushion distortion

Vogel‘s formula for selecting base curve:
For plus lens, Base curve = SE + 6
For minus lens, Base curve = (SE +6) /2

In Pelli–Robson contrast sensitivity letter chart, there is decreasing contrast of 0.15 log
units for groups of three letters.

There are 400 smaller 5 mm squares in AMSLER GRID and when viewed at about one-third
of a metre, each small square subtends an angle of 1°.

For FAF, a pre-injection study is performed with both the excitation and barrier filters in
place.

Pseudoisochromatic plates: falsely or apparently isochromatic; plates that appear
isochromatic to individuals with color-vision abnormality but they are not isochromatic in real.

Antimetropia: hypermetropia in one eye and myopia in other eye.
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
Optics of corrected Aphakes is like Galilean telescope and so image is magnified, while
optics of overcorrected myopes if like Reverse Galilean telescope and hence the image
is minified.

Phi Phenomenon: optical illusion of perceiving continuous motion between separate
objects viewed rapidly in succession. The phenomenon was defined by Max Wertheimer in
the Gestalt psychology in 1912 and along with persistence of vision formed a part of the
base of the theory of cinema, applied by Hugo Münsterberg in 1916.

Jackson cross cylinder (JCC):
o
To define the astigmatic axis: the handle of the lens parallel to the axis
o
To define the astigmatic power: the handle is 45 degrees to the axis.
o
Define the axis before the power

Maddox rods are cylinders of high plus power. Light is focused very close to the rods
forming real image (too close to actually see); and a virtual image perpendicular to these
lights is visible at some distance.

In direct ophthalmoscope, field of vision is always smaller than field of illumination.
(D: I>V)
In INDIRECT ophthalmoscope, field of vision is always larger than field of illumination.
(I: V>I)

In near vision jaeger chart, one point is equal to 1/72 of an inch.

A person who did not receive optical correction for severe astigmatic refractive error in
childhood sometimes shows persistent impairment of corrected vision that is confined to the
more ametropic meridians. This phenomenon is known as meridional amblyopia.
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
Polaroid is made of an extremely thin layer of many fine crystals of iodine and quinine
sulfate. This compound, known as herapathite, after its discoverer W.B. Herapath, is unique
in that it strongly absorbs one of its double-refracted beams so that light vibrating in only one
direction gets through.

Weber's law: for a difference to be detectable, that is, to exhibit a just noticeable difference,
it must be a nearly constant fraction of the background luminance, or /\L/L = constant. This
ratio is about 1% for brightness discrimination and was extended it to other senses

Drop-ball test:
o
To be considered impact resistant, a lens must pass the dress ophthalmic lens dropball test.
o
lens must be able to withstand the impact of a 5/8-inch (15.875-mm) steel ball
dropped from a height of 50 inches (1.27 m) onto the lens front surface.
o
The FDA-mandated drop-ball test results in an impact energy of 0.2 joules (J) or 0.15
foot-pounds (ft-lb) on the lens front surface. Many simple accidents and sports
missiles result in energies that exceed this value by anywhere from 2 to 100 times.

Cornea

The cornea of the body‘s highest densities of nerve endings; and the sensitivity of the
cornea is 100 times that of conjunctiva. Thus cornea is MOST sensitive structure in the
body and BRAIN is the LEAST sensitive structure in the body..!!
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Fungal hypopyon has convex upper border, hyphae seen, low mobility with head posture
and yellow in color.
Bacterial hypopyon has a concave border, mobile with head posture, no hyphae seen and
whitish in color.

Most abundant GAG in cornea: keratin sulfate 65%

Cornea is Meniscus Lens. (Convex Concave). It‘s minus meniscus lens. But in the body is
acts as converging lens i.e. plus lens. If in vitro, it will act as real minus meniscus lens i.e.
diverging lens.
Plus Meniscus: Steep anterior, Flat posterior converging
Minus Meniscus: Flat anterior, Steep anterior  divergent

Prolate: (eg. Egg on its Tip) Steeper front, flat side  causes positive spherical abberations.
(CORNEA is prolate)
Oblate: (eg. Egg on its Side) Flat front, steep side.  causes negative spherical
abberations.

Cornea has positive spherical aberrations.
Lens has negative spherical abberations.

In placido based topography, central point cannot be measured this is in contrast to
Scheimpflug imaging which measures central point most accurately.

Identifying Ectasia on pentacam:
Elevation on anterior float: 12-15 um suspicious, >15 um abnormal
Elevation on posterior float: 17-20 um suspicious, >20 um abnormal

After placing INTACS, cornea becomes more prolate.
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Keratitis with lid lesions: zoster, chickenpox, molluscum contagiosum, and ulcerative
blepharitis with keratitis caused by staphylococcal infection.
Keratitis without lid lesions: vaccinia, adenoviral infections (types 3, 7, and 8 and 19),
chlamydial infections, herpes zoster and Epstein-Barr keratitis.

Papillae in lower fornix are generally not found in vernal conjunctivitis.

Common causes of DLK are: Meibomitis, bacterial endotoxin, marker ink, microkeratome
blade debris, preservatives in drops, interface hemoglobin.

Important complication of trachoma is dry eye due to fibrosis of the upper fornix affecting
accessory lacrimal glands.

In angular conjunctivitis caused by Moraxella axenfield diplo bacillus, maceration of skin is
due to proteolytic enzymes secreted by the bacillus.

The cornea magnifies the image of iris by 10%.

Hirschberg‘s sign: Pale round spots (Koplik spots) on conjunctiva and caruncle in
measles

Basal tear secretion = 2 μL/min

Keratinization of the caruncle is a common early sign of mucous membrane
pemphigoid.

In GPC, In contrast to VKC, keratopathy is rare due to less secretion of toxic cytokines.
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
In SJS, contrast to ocular pemphigoid, immunosuppression is not required prior to
conjunctival or lid surgery.

In PUK, Unlike Mooren ulcer the process may also extend to involve the sclera.

Rizutti‘s sign: Triangle of light on iris from oblique penlight beam focused by cone in
keratoconus

In Thygeson superficial punctate keratitis, conjunctiva is uninvolved and
vascularization is not a feature. The most common differential diagnosis is staphylococcal
hypersensitivity, punctate epitheliopathy or adenoviral keratitis.

Central cloudy dystrophy of François is similar to crocodile shagreen but is
differentiated by its posterior location and AD inheritance.

Kayes‘ dots: Subepithelial infiltrates in corneal allograft rejection

Khodadoust line: Corneal graft endothelial rejection line composed of inflammatory cells

Deficiency of the mucin layer may be a feature of both aqueous deficiency and
evaporative states.
Goblet cell loss is associated with cicatrizing conjunctivitis, vitamin A deficiency, chemical
burns and toxicity to medications.

Follicles are usually seen in viral and chlamydial Conjunctivitis. F-VC
Trachoma
Acute follicular conjunctivitis
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Chronic follicular conjunctivitis
Benign (School) folliculosis
Papillae are usually seen in allergic and bacterial conjunctivitis. P-AB
Trachoma
Spring catarrh
Allergic conjunctivitis
Giant papillary conjunctivitis

Epithelial downgrowth has been reported most commonly as a complication of cataract
surgery, but it can occur after penetrating keratoplasty, glaucoma surgery, penetrating
trauma, and partial removal of epithelial cysts of the anterior segment.
Irradiation and photocoagulation have been abandoned as ineffective.
Excision of involved iris tissue with cryotherapy to remaining corneal membranes is
currently the best technique, although good vision is maintained in only a few cases.
Prevention is much more effective than the treatment of established disease.

Keratoconus is rare in diabetes. Diabetes, Aging and Smoking increases corneal collagen
cross linking just like C3R.

Membrane on conjunctiva:
o
o
True membrane:

Greyish white dense membrane covering both the bulbar and palpebral
conjunctiva

Densely adherent, bleeds on attempting to remove

Corynebacterium Diphtheria
Pseudo membrane:
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
Whitish membrane, not as dense, irregularly covering bulbar and palpebral
conjuoctiva.

Not as densely adherent, comes off comparatively easily

Streptococcus pyogenes

Infectious Crystalline Keratopathy ICK is most commonly seen after  post keratoplasty.

MCC of ICK is streptococcus viridans.

The corneal endothelium and stroma are derived from the neural crest, but the
epithelium is derived from surface ectoderm.

Keratoconus is typically associated with Marfan's syndrome. Keratoglobus is typically
associated with Ehlers-Danlos syndrome.

In congenital hereditary stromal dystrophy, the cloudy stroma is of normal thickness,
and the epithelium is normal. In congenital heriditary endothelial dystrophy (CHED), there
is epithelial edema and a thickened stroma. In both conditions, intraocular pressure (IOP) is
usually normal.

Arcus senilis shows deposition of lipid in all layers of cornea.

The limbal lesions in vernal keratoconjunctivitis are more papilliform because they have a
central vascular core.
When a central pit full of degenerated eosinophils forms, the term Horner-Trantas dot is
applied.

Horner-Trantas dots are clumps of degenerated eosinophils, whereas Herbert's pits are
depressed, necrotic follicles at the limbus.
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Small changes in corneal shape do occur throughout life:
o
In infancy, the cornea is fairly spherical
o
In childhood and adolescence, probably due to eyelid pressure on a young tissue,
cornea becomes slightly astigmatic with the-rule (WTR)
o
In the middle age, cornea tends to recover its sphericity
o
Late in life, against-the-rule (ATR) astigmatism tends to develop.

Unlike Scheimpflug based topographers, Placido-based topographers measure angle
kappa.

The cornea transmits radiation from approximately 310 nm in the ultraviolet to 2500 nm in
the infrared region.
The cornea is extremely sensitive to UV radiation at 270 nm and corneal absorption of this
radiation results in photo keratitis after exposure to welding arcs.

Conjunctival papillae form whenever there is conjunctival swelling of any cause in certain
areas. The tarsal and limbal conjunctiva is unique because their subepithelial substantia
propria contains fibrous tissue septa that interconnect to form polygonal lobules with a
central vascular bundle. Any inflammation in these regions will result in papillae. Papillae <1
mm in diameter are entirely nonspecific. When papillae are >1 mm in diameter (giant
papillae), they are more specific.
Most young people with healthy eyes will have small conjunctival papillae along the superior
margin of the upper tarsus

Conjunctival follicles represent focal lymphoid aggregates in the substantia propria.

In GPC, the inferior fornix is generally the least involved, whereas in viral conjunctivitis,
it tends to be the most severely involved.
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Follicular conjunctivitides are typically more severe inferiorly than superiorly except for
trachoma.
This is in stark contrast to inclusion conjunctivitis, another chlamydial disease, which is
more severe inferiorly.

Neonatal inclusion conjunctivitis may be pseudomembranous or membranous, but this is
rare in adults.

Typical microcystic corneal epithelial edema is in the intercellular space and results from
an imbalance between corneal turgescence (swelling due to intraocular pressure [IOP]) and
deturgescence (drying due to endothelial pumping).
Intracellular epithelial edema does occur, as a result of epithelial hypoxia, but this appears
different clinically— as a fine, frosted-glass appearance (Sattler's veil), generally
associated with contact lens use.

Sattler‘s veil: Superficial corneal edema (bedewing) caused by hypoxia (contact lens)

Development of corneal epithelial filaments—increased mucus production along with
increased, deranged epithelial turnover. The filaments themselves are composed of mucus
and desquamated epithelial cells.

KPs: Lymphocytes & PMNs
Mutton-fat KPs: Macrophages, greasy look

Endophthalmitis rates are higher with laser-assisted in situ keratomileusis (LASIK) than
with photorefractive keratectomy (PRK). LASIK does offer a reduced incidence of stromal
haze and more rapid epithelial healing. Photorefractive keratectomy (PRK) can have
significant postoperative pain. PRK offers a reduced incidence of endophthalmitis and
corneal perforation.
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fluorescent treponemal antibody-absorption (FTA-ABS) and microhemagglutination of
Treponema pallidum (MHA-TP), are the closest to a ―gold standard‖ for syphilis testing.
The Venereal Disease Research Laboratory (VDRL) and rapid plasma reagin (RPR) tests
reflect treponemal infection and revert to normal when treated. The value of these tests is
primarily to monitor response to treatment because they are less sensitive and specific.
The fluorescent treponemal antibody (FTA) and microhemagglutination of Treponema
pallidum (MHA-TP) offer greater sensitivity and specificity and do not normalize with
treatment. They are lifelong markers of previous or active treponemal infection.

Fusarium has septate hyphae, whereas Mucor has nonseptate hyphae.

Intranuclear inclusion bodies of herpes simplex virus (HSV) epithelial infection: Lipschütz
bodies (Papanicolaou (Pap) smear)

multinucleated giant cells seen in epithelial herpes simplex virus (HSV) infection: Tzanck
prep (Giemsa stain)

A granulomatous reaction to Descemet's membrane (including multinucleated giant
cells) is most frequently seen with disciform keratitis with a history of herpes simplex or
herpes zoster keratitis. This peculiar reaction to Descemet's membrane may be related to an
altered antigenicity of the membrane and subsequent development of an autosensitivity
reaction. This reaction is very uncommon with other etiologic agents.

There are five anti-Epstein-Barr virus (EBV) antibodies:
1. viral capsid antigen (VCA)-IgG
2. VCA-IgM
3. early antigen-diffuse (EA-D)
4. EA-R (early antigen-restricted)
5. Epstein-Barr nuclear antigen (EBNA)
Only EBNA does not peak in the first 6 to 8 weeks of infection.
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Viral capsid antigen (VCA)-IgG and Epstein-Barr nuclear antigen (EBNA) provide lifelong
evidence of Epstein-Barr virus (EBV) infection.

Like bacteria (and unlike viruses), chlamydiae have both DNA and RNA, replicate by binary
fission, have lipopolysaccharide cell walls, and respond to certain antibiotics. Unlike
bacteria, chlamydiae do not possess all organelles and require a host cell for replication.

Difficult to culture: lyme dz, chlamydia, acanthameba

Double walled cyst appearance: acanthameaba

In neonatal inclusion conjunctivitis, the likelihood of finding cytoplasmic or intranuclear
inclusions is higher than adult one.

Acyclovir is activated by viral thymidine kinase and is relatively nontoxic to mammalian
cells. Trifluridine (Viroptic) inhibits another virus-specific enzyme, thymidylate synthetase.

Acyclovir is not effective against CMV.

presumed filamentous keratomycosis: topical natamycin TOC

Amphotericin has less predictable activity against filamentous species than natamycin.

polyene class: renal toxicity (POLY-uria)
imidazole: hepatic (ICTerus)

Suspensions must be shaken to be effective.
Acetate preparations (suspensions) are more potent than phosphate preparations.
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
Local steroids do not reactivate latent virus, but caution should be exercised because
intermittent shedding of the virus from the trigeminal ganglion (unrelated to steroid use) may
coincide with steroid use and exacerbate subsequent disease.

Pedunculated conjunctival papillomas are generally associated with human papilloma virus
(HPV) types 6 and 8.
sessile conjunctival papillomas are associated with HPV-16 and HPV-18.

Blephroconjunctivits:
Collarettes indicate Staphylococcus.
Scurf indicates seborrhea.
Sleeving of the lashes is a sign of Demodex infestation.

The most common cause of phlyctenulosis is Staphylococcus, followed by active or latent
tuberculosis.

Neisseria gonorrhoeae is the only bacterial conjunctivitis that causes preauricular
adenopathy.

Gonococcal conjunctivitis: ceftriaxone 1 g intramuscularly daily for 5 days and
doxycycline orally twice daily for 3 weeks. Doxycycline (or tetracycline) is added to treat
potential chlamydial infection (sexually transmitted diseases tend to run together).

Although neonatal inclusion conjunctivitis usually responds to topical therapy, systemic
erythromycin is recommended because of associated chlamydial infections, such as otitis
media and pneumonitis.

Topical antihistamines do not work well in atopic keratoconjunctivitis; systemic
antihistamines are critical for its control.
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
SAC & VKC: SAC response to topical antihistamines & has giant papillae

Type 2 herpes usually resides latently in spinal ganglia.
Dhaval Patel MD
Type 1 herpes: The gasserian (or trigeminal) ganglion, located in Meckel's cave, contains
the cell bodies of the trigeminal nerve.

Wessely's ring: circular, superficial distribution of neutrophils around an area of corneal
edema or inflammation. It is identical to the immunoprecipitate formed in the Ouchterlony
gel.

Topical steroids in disciform keratitis:
1. the visual axis must be involved
2. neovascularization must be progressing

Reactivation and not Reinfection has been reported to lead to typical herpes zoster
ophthalmicus (HZO).

Postherpetic neuralgia: oral TCA & Steroids (7 to 10 days after eruption of active
dermatitis)

Herpes zoster ―dendrites‖ (pseudodendrites) are typically smaller and less branching
than their simplex counterparts.

Cogan's syndrome is frequently associated with polyarteritis nodosa.

About one half of patients with superior limbic keratoconjunctivitis (SLK) have some
form of thyroid disease.
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Treatment of the thyroid disorder, however, has little effect on the SLK.
A recent study suggests that orbital decompression for thyroid optic neuropathy is required
more frequently in patients with thyroidassociated SLK.
steroids are not effective therapy for superior limbic keratoconjunctivitis (SLK).
Surgical resection of the superior bulbar conjunctiva is definitive.

Episcleritis rarely progresses to scleritis; however, episcleritis nearly always
accompanies scleritis.
o
Generally, episcleritis causes minimal pain, whereas scleritis is moderately to
severely painful.
o
Episcleritis is usually of rapid onset as opposed to scleritis, which is usually gradual,
over days.
o
In scleritis, the scleral (deep episcleral) plexus is immobile and bluish-red in color;
episcleritis appears salmon pink.
o
Scleral vessels do not blanch with phenylephrine, as do those in episcleritis.
o
Lastly, scleritis is frequently seen with systemic connective tissue disorders; this is
not true of episcleritis.

Posterior uveitis occurs in virtually all patients with posterior scleritis and is not
uncommon in patients with anterior scleritis. Anterior uveitis occurs in about one third of all
patients with scleritis.

Chronic dacryoadenitis is sometimes accompanied by inflammation and swelling of the
salivary glands, which is referred to as ―Mikulicz's syndrome.‖

Silent dacryocystitis is usually produced by Streptococcus pneumoniae and may
present with no clinical symptoms other than occasional epiphora.

Eyes without any astigmatism will not have any wavefront aberration. Wavefront analysis is
used to analyze irregular astigmatism.
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Munnerlyn's formula: The ablation depth (in microns) is equal to the diopters of myopia
divided by 3 and multiplied by the square of the optical zone (in millimeters). It is most useful
with low amounts of correction (<7 diopters).
Sometimes, 15 microns ablation per diopter of myopia is taken.

Natamycin is a polyene antifungal that is the drug of choice for filamentous fungi.
Topical miconazole is the drug of choice for Paecilomyces lilacinus.
Topical amphotericin is used to combat infections caused by Aspergillus and Candida
spp.
Flucytosine is used as an adjunctive agent for treatment of Candida spp.

Cornea verticillata: amiodarone, chlorpromazine, chloroquine, indomethacin, meperidine,
and tamoxifen.

Kayser-Fleischer ring: Wilson's disease, primary biliary cirrhosis, chronic hepatitis, or
progressive intrahepatic cholestasis of childhood, but only patients with Wilson's disease will
show neurologic findings. KF ring will disappear with appropriate treatment, thereby
providing a means to monitor therapy.

Spheroidal degeneration involves proteinaceous deposits (not lipid) in the superficial
stroma.

In PMD, protrusion of the cornea above the area of maximal thinning inferiorly in the
cornea, whereas in keratoconus, corneal protrusion is at the point of maximal thinning.

CHED: Nystagmus is associated with the recessive, but not the dominant form of the
disease.
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
CHSD is a rare, autosomal dominant condition presenting at birth as a central, anterior
stromal feathery opacity that may cause reduced visual acuity. The corneal periphery is
clear. There is no pain, photophobia, or tearing because IOP is normal.

Dystrophies at birth-natal age groups: CHED, PPCD and CHSD.
PPCD may be differentiated from CHED by the presence of other anterior segment
abnormalities such as endothelial vesicles and bands, a characteristic endothelial pattern on
specular microscopy (if possible), and bridging synechiae in the patient or family.
In CHSD the corneal opacification appears as full-thickness, feathery clouding of the stroma
with a normal corneal thickness. In addition, the histopathology in CHSD shows a normal
epithelium, Bowman's layer, endothelium, and Descemet's membrane. The stroma consists
of tightly packed lamellae with rigidly ordered small-diameter collagen fibrils alternating with
loosely aligned and haphazardly arranged larger-diameter collagen fibrils, distinctive for
CHSD.

Harboyan syndrome (CHED 2 and perceptive deafness (CDPD)) is an autosomal
recessive disease mapped at overlapping loci 20p13.

The most common stromal dystrophy is lattice, followed by granular and macular.

Recurrence in the graft is common in both Reis-Bucklers' dystrophy and lattice
dystrophy.

Patients with Fuchs' endothelial dystrophy have malfunctioning Na-K ATPase pumps in
the lateral cell wall of the endothelial cells. This diminished pump function results in swelling
of the corneal stroma. Cytochrome oxidase is also reduced, which may indicate a decrease
in the metabolic activity of the endothelial mitochondria.

Coroneo Effect: Nasal segment of cornea gets highest UV exposure effect which is
responsible for pterygium.

Most serious ACID INJURY is hydrofluoric acid & MC is sulfuric acid. (Survey ophth)
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Most serious ALKALI INJURY is ammonia/ lye & MC is Lime. (Survey ophth)

precipitation of ciprofloxacin onto the corneal surface do occur. Not with other FQ.

Thygeson's superficial punctate keratitis: HLA-DR3 have a 5.65 greater relative risk.

A number of features are shared between dendritic infection from HSV and HZV.
Both may have an accompanying skin rash (along a dermatome in HZV) and corneal
anesthesia.
The active viral replication causes sloughing of epithelial cells in HSV, whereas in HZV,
the epithelial cells are swollen and heaped up.
Both conditions may recur. Iritis and elevation in IOP can be found with both viral infections;
however, iris atrophy is more common with HZV.

Herpes: intranuclear inclusion bodies (Lipschütz bodies or Cowdry type A inclusions).
Chlamydia: Intracytoplasmic inclusions.

interstitial keratitis
o
bilateral: Congenital syphilis
o
unilateral: Tuberculosis, herpes simplex, and acquired syphilis
o
Cogan's syndrome affects middle-aged adults with hearing loss, vertigo, and
interstitial keratitis.

thinnest paracentral quadrants of cornea (in descending order) are the temporal (28%),
inferior (19%), nasal (11%), and superior (4%). TINS

Pingueculae: ultraviolet light, changes in the subepithelial collagen. Although these fibers
stain with some elastin stains, the fibers are not true elastin and will not be degraded by
elastase. This finding is known as ―elastosis.‖
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
Epithelial downgrowth is usually more aggressive than fibrous downgrowth.

Agents that have been used for Acanthamoeba include- neomycin, natamycin, miconazole,
propamidine, dibromopropamidine, polyhexamethylene biguanide, and chlorhexidine.

Oval graft with the long axis at 90° produces against-the-rule astigmatism (and therefore
neutralizes with-the-rule astigmatism common to circular grafts).

Rapid onset of corneal stromal opacity following episcleritis  sclero-keratitis.

Epikeratoprosthesis (forerunner of epikeratoplasty techniques): used in Aphakic bullous
keratopathy-it relieves pain and improves vision. Complications are Stromal
vascularisation, infection, growth of epithelium beneath lens causing it to become dislodged.

Coats‘ ring: White granular corneal stromal opacity containing iron from previous metallic
foreign body

Although keratitis is not universal in patients with herpes simplex virus (HSV) uveitis, it is
usually present in affected children.

More than 50% of uveitis in the pediatric population has a posterior component.

The brain and retina (a part of the brain) are the sites where Toxoplasma organisms
survive best.

TBUT should be done first as a Schirmers would create an artificial dry spot to appear at
the point of its contact with the eye, thus falsely reducing the TBUT.
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Dhaval Patel MD
Schirmer's test:
Schirmer's II (with anesthesia) has been purported to measure ‗basal‘ tear secretion, i.e.
nonstimulated tears. Values below 5.5 mm of wetting are diagnostic of aqueous tear
deficiency.
A Schirmer's I (without anesthesia) has become the generally accepted method for
assessing aqueous tear production. It measures both basal and reflex tear secretion.
REMEMBER this by test 1 measures 2 things and vice versa. Test 3 is with nasal irritation.

Systemic conditions associated with posterior scleritis are: rheumatoid arthritis,
Ankylosing Spondylitis, Reiter's syndrome, polyarteritis nodosa and systemic lupus
erythematosis.

In case of GPC, in vernal catarrh the reaction is IgE mediated and in Giant papillary
conjunctivitis the reaction is type 1 or type 4 hypersensitivity reaction.

Recurrence of corneal dystrophy: Reis-Bückler > macular > granular > lattice

Corneal dystrophy associated with glaucoma: PPCD

TC- 199 = tissue culture medium 199

Riboflavin is hydrophilic solution so during C3R, ideally epithelium should be removed.

The Athens Protocol: The management of keratoconus and post-LASIK ectasia by means
of combined, same-day, topography-guided partial PRK and collagen cross-linking.

The excimer laser was originally applied to the cornea to produce more accurate RK
incisions, not for surface ablation or laser in situ keratomileusis (LASIK), for which the
excimer laser is now used.
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
Arcuate keratotomy differs from LRIs by its midperipheral location and its greater relative
depth.

Studies have demonstrated that up to 15° of cyclotorsion can occur when patients move
from an upright to a supine position.

Ligneous conjunctivitis is actually a genetic disease.
It results from homozygous mutations in the PLG gene (6q26) that codes for
plasminogen and therefore is inherited in an autosomal recessive pattern. Tears contain
plasminogen activators that convert plasminogen into the fibrinolytic enzyme plasmin
which normally clears conjunctival and corneal fibrin deposits. The lack of normal
plasminogen allows fibrin to accumulate on all mucosal surfaces.

Pingecula are histologically ACTINIC ELASTOSIS.

Concretions are collection of inspissated protein within the pseudoglands of henle.

Most accurate method for RSBT measurement: intraoperative measurement after
creating flap by UBM.

Corneal infection with bloody looking perfotation  Moraxella

McCoy cell culture is highly specific for TRIC.

Tobramycin is better than gentamycin only in pseudomonas, but as pseudomonas is
one of the infections we should worry about, we start generally tobramycin instead
gentamycin. If you are sure that it‘s not going to be pseudomonas, you can start gentamycin
also.
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
Dhaval Patel MD
Tsukamurella keratitis
o
gram-positive bacilli
o
severe eye pain, typical of bacterial keratitis
o
infiltrates in the peripheral parts of the cornea near the limbus, resembling that of
marginal keratitis.
o
relatively less virulent nature
o
microtrauma to the epithelial surface of the cornea
Corneal Nerves
o
o
Prominent corneal nerves:

Keratoconus.

Ichthyosis

Fuchs corneal (Reis-Buckler's ) dystrophy

Corneal edema

Congenital glaucoma

Acanthamoeba Keratitis

corneal graft failure.

Trauma.

Idiopathic.
Enlarged Corneal Nerves:

MEN IIb

Phytanic acid storage dis (Refsum syndrome).

Hansen dis (leprosy,beading of nerves

Familial dysautonomia(Riley- Day)

Neurofibromatosis.

Acanthamoeba perineuritis.
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primary amyloidosis

sequential sector conjunctival epitheliectomy (SSCE): for partial LSCD involving the visual
axis

Corneal Hysteresis: measure of viscous damping of cornea

Corneal resistance Factor: measure of resistance/rigidity of cornea

Boston scleral lens= PROSE: Prosthetic Replacement of the Ocular Surface Ecosystem,
sed for irregular corneas

Concentration of riboflavin for C3R: 0.1%, in 20% dextran, 30 min, 370 nm, 3 mW/cm2

In corneal blood staining, hemoglobin products accumulate in corneal stroma. (not
RBCs)

Progression of bacterial corneal ulcers: Proteases released by bacteria

Most stable flap in femtosecond laser: zig-zag

Flat cornea: <41D, Free cap, thick flap
Steep cornea: >50D, Buttonhole, thin flap

Q value: Corneal asphericity
o
By applying certain mathematical equations, eccentricity can be calculated and
given a value from which Q-value can be derived.
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o
Positive: center of the cornea is flatter than the periphery, oblate cornea
o
Zero: center equals the periphery, sphere cornea
o
Negative: center is steeper than the periphery, prolate cornea
o
Q-value is considered normal when it falls between 0 and -1 [-1, 0].

PPMD: AD, incomplete penetrance, variable expression, 20q11

Macular dystrophy: hypo/non-sulfated keratin

Bacterial ulcer simulating fungal ulcer: Hyphate edges, satellite lesion
o
Nocardia: calcerous bodies
o
Actinomyces
o
Streptomyces

Corneal sensations are normal in adenoviral keratitis.

Goblet cells are most dense in inferonasal quadrent.

Acanthameba transport media: page‘s medium
Virus transport medium: Hank‘s medium
Chlamydia transport medium: 0.2M sucrose phosphate medium

w3 fatty acid  anti inflammatory products like PGE3, LBT5
w6 fatty acid  pro inflammatory prodcts like PGE1, PGE2, LBT4

HBID: Hereditary benign intraepithelial dyskeratosis
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o
Also called Witkop von Sallman syndrome, red eye disease
o
Acanthotic and dyskeratotic epithelium of conjunctiva and oral mucosa
o
Rare, autosomal dominant disease with incomplete penetrance, which usually
appears in first decade of life
o
Originally described in Haliwa Indians in North Carolina (USA), also elsewhere in
US and Europe
o
Gray-white, inflamed, horseshoe shaped elevated lesions of conjunctiva and oral
mucosa; bilateral corneal involvement

ProClear Contact Lens: biocompatible omafilcon, a material with phosphorylcholine
integrated into lens polymer. PC molecule attach to H2O allowing the lens to resist deposits
and thus function better.

Acid injuries causes less damage than alkalies in general except Hydrofluoric acid
used in glass etching and cleaning also tends to rapidly penetrate the eye, whilst sulphuric
acid may be complicated by thermal effects and high velocity impact after car battery
explosions.

Unlike CHQ-HCHQ retinopathy, vortex keratopathy caused by them bears no relationship
to dosage or duration of treatment. The changes are usually reversible on cessation of
therapy, although they may clear despite continued administration.

Phenol red thread test uses a thread impregnated with a pH sensitive dye. The end of the
thread is placed over the lower lid and the length wetted (the dye changes from yellow to red
in tears) is measured after 15 seconds. A value of 6 mm is abnormal. It is comparable to
Schirmer test but takes less time.

Zidovudine, an anti-retroviral agent, may be beneficial in primary Sjögren syndrome.

The adenoid superficial layer of the conjunctiva does not develop until about 3 months
after birth, hence the inability of the newborn to produce a follicular conjunctival reaction.
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In hyperacute conjunctivitis caused by Neisseria, drug of choice is
o
Ceftriaxone 1 gm IM + azithromycin 1 gm PO
o
Azithromycin is given to treat concurrent chlamydia infection.
o
Even if concurrent chlamydia is not suspected, treat with both drugs as azithromycin
covers ceftriaxone resistance.

Hertoghe sign is characterized by absence of the lateral portion of the eyebrows. It is seen
in Atopic Keratoconjunctivitis.

Mucus fishing syndrome: in a variety of underlying anterior segment disorders, patients
develop or exacerbate a chronic papillary reaction due to repetitive manual removal of
mucus which results into GPC like state.

Ocular Protection Index (OPI): OPI = BUT/IBI.
Values below 1 are characteristic of tear film instability and dry eye disease. Blink rate,
which is calculated by dividing 60 by the number of observed blinks per second. (IBI: InterBlink Interval)

Meibography is a technique that uses transillumination biomicroscopy of the everted eyelid
with infrared photography
Meibometry is used to measure the amount of lipid on the lid margin by determining the
degree of translucency induced on plastic tape applied to the lid margin.

Tetracycline reduces lipase production in S. epidermidis, S. aureus, and P. acnes.
It also decreases serum cholesterol in mice, has antichemotactic effects on neutrophils,
and has activity against collagenase and other metalloproteinases.
Any of these properties may produce a marked therapeutic effect in many patients with
meibomian gland dysfunction and rosacea.
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
The currently accepted WHO guidelines include community-wide antibiotic treatment if there
is >10% active trachoma in children aged 1–9 years. This treatment should be
reinstituted annually for 3 years, with reassessment at that time.

In contrast to VKC, the papillary hypertrophy of AKC is more prominent in the inferior
conjunctival fornix.

keratotorus = Schlappi’s pellucid marginal degeneration

Cause of the foamy appearance of the Bitot's spot: due to gas production by
Corynebacterium xerosis in the horny epithelium

Types of xerosis:
o
Xerosis epitheliasis - Due to vitamin A deficiency and associated with protein
energy malnutrition.
o
Xerosis parenchymatas - Sequale of ocular inflammation  Trachoma, Chemical
injury, Diphtheria, Ocular pemphigoid

Anterior stromal cautery: Application of light burns to Bowman's layer using a thermal
cautery (Salleras procedure)

Unlike meibomian gland secretion, sebum contains more triglycerides and free fatty acids
and considerably less sterol esters. Squalene is present in sebum and absent in meibomian
gland secretion. The wax ester proportion is similar in both secretions. Overall, sebum is
much more polar and will contaminate the tear film when mixed with it.

Large-diameter lamellar grafts: Malbran procedure  advanced keratoconus
Malbran‘s ―peeling off‖ technique is the safest lamellar keratoplasty procedure and yields
postoperative visual results equal to the more risky deep lamellar techniques.
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
Follicular reactions are not seen in the neonate because of the immaturity of the immune
system and adenoid layer of conjunctiva is not matured till 3 months.

Corneal Collagen Cross-linking C3R:
1. Biomechanical stabilization:

primary and secondary keratectasia

4-fold increase of stiffness of the anterior cornea
2. Biochemical stabilization:

crosslinked collagen is more resistant against digesting enzymes

crosslinks are produced in the outer surface of the collagen molecule,
blocking the docking stations for enzymes, and therefore the enzymatic
activity is blocked

melting can be stopped
3. Cytotoxic effect:


killing keratocytes up to 350 μm deep in the cornea

also used to kill germs
Enhancers for Epi-On C3R
o
Trometamol (Tris-[hydroxymethyl]aminometane)
o
Sodium ethylenediaminetetraacetic acid (EDTA)
o
Benzalkonium chloride BAC

Contact lens cornea is seen in rheumatoid arthritis.

Keratoconus indices
o
Keratoconus Severity Index KSI >0.15
o
Keratoconus Predicctability Index KPI >0.23
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o
Dhaval Patel MD
Keratometry Inferior Superior Asmmetry KISA >100%

Posterior elevation >40um on orbscan precludes LASIK.

INTACS
o
150 degrees
o
PMMA segments
o
7.5 to 8.1 mm
o
68% depth
o
250-400 microns thick

CALAK: Corneal Augmentation Lamellar Keratoplasty, combination of LASIK and
keratophakia

Post PRK stromal Haze increases after UV-B exposure.

DLK can induce hyperopia.

Most common cause of acute conjunctivitis: streptococcus pneumonia
Most common cause of chronic conjunctivitis: staphylococcus aureus
Most common cause of blephroconjunctivitis: staphylococcus aureus
Most common cause of chalazion: staphylococcus aureus

Conjunctival SCRAPPING is done for chlamydia and viruses as they are intracellular,
conjunctival SWAB is taken for bacteria.
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Dhaval Patel MD
Newer therapy to prevent graft rejection:
o
FK 506
o
Rapamycin
o
15-deoxypergualin
o
Anti CD-154 antibody
o
antiVEGFs
o
leflomide

The ring-shaped stromal infiltrate seen in herpes simplex keratitis is thought to be
similar to the line of precipitation in the Ouchterlony test. Antigens diffuse from one area of
the gel and antibodies diffuse from another. The line forms at the meeting point of the
diffusing antigen and antibodies.

All hyperlipoproteinemias except TYPE I are associated with arcus.

Conjunctival Sickle Sign: Abnormalities of the bulbar conjunctival blood vessels provide
direct evidence of the vaso-occlusive process and were one of the earliest reported ocular
changes.

Acanthameba Stains:

o
The trichrome-eosin and iron-hematoxylin stains showed good color contrast for
detecting all three stages, the trophozoite, cyst and flagellate
o
Giemsa and Gram stained the trophozoite and flagellate stages;
o
Modified Field‘s and modified AFB stains stained only the trophozoite stage.
o
Depending on the purpose, all these stains (except the AFB stain) can be used.
In pterygium, IL-7 is decreased.
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

LASIK Interface Fluid Syndrome
o
first described by Lyle and Jin in 1999
o
accumulation of fluid in the LASIK flap interface due to steroid induced IOP spike,
uveitis, and vitreoretinal and cataract surgery, as well as endothelial decompensation
Corneal Inlays
o
o
o

Dhaval Patel MD
Pinhole Corneal Inlays

small-aperture corneal inlay (Kamra, AcuFocus; Irvine,Calif., USA)

for the correction of presbyopia is based on the principle of changing the
depth of focus

ACI 7000
Refractive Corneal Inlays

intracorneal inlay Flexivue Microlens

Presbia

Hydrophilic acrylic
Nonrefractive Inlays

Raindrop (Vue+; Revision Optics)

Hydrogel
Corneal Laser Surgery in Presbyopia
o
o
Multifocal ablations

Supracor (Bausch + Lomb Technolas; Munich, Germany),

PresbyMAX (Schwind Eye-Tech-Solutions GmbH and Kleinostheim,
Germany)

Pseudoaccommodative cornea (PAC; Nidek Co. Ltd.; Gamagori, Aichi,
Japan)
Monofocal ablations
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classic monovision LASIK

laser blended vision (Carl Zeiss; Germany)
Dhaval Patel MD

A rare clinical syndrome consisting of a fixed dilated pupil, iris atrophy, and glaucoma,
known as Uretts-Zavalia syndrome, has been observed following penetrating keratoplasty
and deep lamellar keratoplasty for keratoconus.

Photochemical keratodesmos
o
method of producing sutureless adhesion by applying a photosensitizer to wound
surfaces followed by low energy laser irradiation.
o
The laser promotes crosslinking between collagen molecules on opposing surface to
produce a tight seal without inducing thermal damage to adjacent tissue.
o
It uses rosebengal dye, which activated by low energy argon ion laser at a
wavelengtyh of 514 nm.
o
This Photochemical keratodesmos system may be useful adjunct to sutures in
immediate postoperative period

A randomized, masked clinical trial of 18 participants allergic to grass pollen found that
signs of allergic conjunctivitis were reversed most effectively by CCs plus ATs or EH
drops; however, hyperemia was reduced more by ATs combined with CC than other
treatments.

Prospective Review of Early Cataract Outcomes and Grading (PRECOG) study

o
designed to test new approaches for the measurement of cataract surgical quality in
settings with poor rates of follow-up.
o
The study, conducted at 40 centers in 11 countries in Asia, Africa, and Latin
America, shows that visual outcome measured at 3 days after cataract surgery
correlates well with long-term outcome and can be used as a measure of surgical
quality in regions of the world in which longer-term follow-up is rare.
Brown-McLean Syndrome:
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o
rarest and most benign form of corneal edema
o
peripheral corneal stromal and epithelial edema that spares the central and superior
cornea with pigment deposits are present on the underlying endothelium
o
A central zone of 5–7 mm remains clear and compact indefinitely despite the
peripheral edema.
o
The peripheral iris may show transillumination, but the trabecular meshwork is not
necessarily hyperpigmented.
o
If the patient is bilaterally aphakic, the syndrome is usually present in both eyes.
o
There is no clinical inflammation, and the cause is unknown.
o
Although the classic presentation follows intracapsular cataract extraction, it may
occur after extracapsular cataract extraction

The adenovirus test, which detects the most common cause of viral conjunctivitis, requires
only 10 minutes to develop after sample collection. It uses direct sampling microfiltration,
similar to a home pregnancy test, to produce visual results, with a blue control line and, if
positive, a red test line. Compared with cell culture, the traditional definitive test for
adenovirus infection, this rapid test has a 90% sensitivity and a 96% specificity.

The ‗pump-leak‘ hypothesis: When the rate of fluid leakage into the stroma is balanced by
the rate of fluid pumped out of the stroma, normal corneal architecture and thickness are
maintained.

Indications for Simultaneous Keratoplasty in Cataract Surgery

o
Frank epithelial edema, or
o
Blurry vision in the morning, or
o
Corneal thickness above 0.70 mm, or
o
Endothelial cell density less than 500 cells/mm2
Location of corneal epithelial stem cells (SC): basal layer of the limbus
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Thoft and Friends‘ X, Y, and Z hypothesis of corneal epithelial maintenance
o


X+Y = Z

X= proliferation of basal cells

Y= centripetal movement of cells

Z=cell loss from the surface
Specular Microscopy Finding in Posterior Corneal Disorders
o
Fuchs‘: decreased ECD, polymegathism, pleomorphism, disruption from guttae
o
PPMD: Pleomorphism, irregular large cells with scalloped edges as dark rings
around lighter center, vescicles/pits in DM, Disrupted by crater-like focal lesions
o
ICE: enlarged ICE cells, white reflections in center of dark cells ‗dark-light reversal‘,
no disruption from craters or guttae
TYROSINEMIA
o
o

Dhaval Patel MD
type 1

most common

hepatorenal tyrosinemia

deficiency of fumarylacetoacetate hydrolase

no corneal involvement
type 2

oculocutaneous tyrosinemia or Richner–Hanhart syndrome

deficiency of hepatic tyrosine aminotransferase, the gene for which is located
on chromosome 16q22

can develop superficial punctate crystalline lesions, often in a dendritiform
pattern, that may mimic HSV keratitis
Left eyes seem to be affected more commonly than right eyes because neonates usually
present in the left-occiput-anterior position
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Peters‘-plus syndrome: Peters‘ anomaly + short stature, brachymorphy, mental
retardation, abnormal ears, and, in some patients, cleft lip and palate
Krause-Kivlin syndrome: Peters‘ anomaly + facial abnormalities, disproportionate short
stature, retarded skeletal maturation and developmental delay (probably inherited in an
autosomal recessive manner)

Unlike meibomian gland secretion, sebum contains more triglycerides and free fatty acids
and considerably less sterol esters. Squalene is present in sebum and absent in meibomian
gland secretion. The wax ester proportion is similar in both secretions. Overall, sebum is
much more polar and will contaminate the tear film when mixed with it.

Lens

Juvenile xanthogranuloma (JXG) can cause spontaneous hyphemas. However, in any
infant that presents with ―spontaneous hyphema,‖ an ophthalmologist must consider child
abuse. Other causes of spontaneous hyphema include bleeding diatheses, leukemia, and
retinoblastoma.

Lens does not contain hydroxyProlene, Cysteine and Tryptophan. (PCT)

Predominant cation in lens is K+ and anion is PO4-.
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Cataracts may occur both in galactosemia (galactose-1-phosphate uridyltransferase
deficiency: GAL1PUT) and galactokinase deficiency.
Galactosemia, however, also can feature hepatosplenomegaly, mental retardation, and
other systemic manifestations.

Neurofibromatosis type 2, not type 1, may be associated with posterior subcapsular
cataracts (and acoustic neuromas as well).

Posterior capsule opacification, glaucoma (angle closure caused by excessive
inflammation), and retinal detachment (caused by vitreous loss) are more common
postoperative complications in children undergoing cataract extraction.
The incidence of cystoid macular edema (CME) is lower in children than in adults.

Polyopia, pupillary block, and corneal-lenticular touch are indications for medical or
surgical intervention in lens subluxation (which can be accomplished with the implantation of
a Morcher endocapsular tension ring).
Decreased vision often can be corrected solely with an aphakic refraction.

Pyramidal cataracts are a distinct and more severe form of anterior polar opacity, named
because the shape of the anterior opacity resembles a pyramid. A more accurate and
modern description is a likeness to the shape of the chocolate candy called the Hershey's
Kiss. The tips of these opacities extend into the anterior chamber and rarely have even
been known to be fused with the cornea. They are fibrous and may be associated with an
anterior subcapsular cataract that, when present, often progresses to become visually
significant. At surgery, the fibrous ―Hershey's Kiss” is not easily removed with the
vitreous cutter. After it is detached from the anterior capsule, it usually spins around the
anterior chamber and has to be delivered through the incision using forceps. These
pyramidal cataracts are almost always bilaterally symmetric and may be dominantly
inherited.

Homocystinuria
o
It is AR with the gene locus on chromosome 21q.22.3.
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o
Affected patients are generally tall with osteoporosis, scoliosis, and chest
deformities.
o
About 50% of the time there is associated mental retardation.
o
These patients are at increased risk of thrombotic vascular occlusions, and this
should be taken into consideration if general anesthesia is planned.
o
Lens dislocation occurs in 90% of patients and is generally inferior and bilateral.
o
Homocystinuria may lead to angle closure glaucoma if the lens dislocates into the
anterior chamber.
o
In homocystinuria, serum levels of homocystine and methionine are elevated.
Patients are normal at birth but develop seizures, osteoporosis, and mental
retardation. Classic lens dislocation is bilateral, symmetric, usually inferonasal.
o
Decreased hepatic activity of cystathionine beta-synthase results in systemic
accumulation of homocysteine and methionine.
o
Normal lens zonules have a high concentration of cysteine, and deficiency
results in abnormal, brittle zonules.
o
A diet low in methionine and high in cysteine can reduce lens dislocation.
o
Vitamin B6 supplementation have shown promise in treating these patients and in
reducing ectopia lentis.

The Malyugin ring is a device to enlarge a small pupil and/or stabilize an atonic iris. This
may be necessary in patients with pilocarpine treatment, pseudoexfoliation, and IFIS.
Pupillary dilation is usually not an issue in ectopia lentis.

Z-syndrome refers to a complication of the Crystalens in which the plate haptics are bent
asymmetrically so the lens has a ―Z‖ configuration.
Z phenomenon: earliest models of foldable IOLs were too long, so that when they were well
fixated within the capsular bag they caused wrinkling of capsule centrally because of
capsule contraction.

Coloboma of the lens is not a true coloboma. Instead the notch in the equator resulted from
an absence of zonular fibers from an underlying colobomatous ciliary body. This absence
results in a lack of tension on the lens capsule in that region. The lens tissue is not missing.
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Ectopia lentis associated with mental retardation:
o
Hyperlysinemia
o
Weill-Marchesani syndrome
o
Homocystinuria

Young, myopic males may be predisposed to pigmentary dispersion syndrome.

Amiodarone and phenothiazine cause stellate cataracts in the anterior lens capsule.
All forms of steroids have been associated with cataract formation.

Persistent hyperplastic primary vitreous (PHPV) is a congenital, nonhereditary ocular
malformation. Associated findings include elongation of ciliary processes, prominent radial
iris vessels, persistent hyaloid artery, microphthalmia, and ectopia lentis.

Monocular visual deprivation, most likely with nuclear cataract, is the most ―amblyogenic.‖

Vitamin B6  homocystinuria
Coenzyme Q  Leber's hereditary optic neuropathy
Vitamin A  retinitis pigmentosa

20% of patients with cataract have significant preexisting astigmatism.

Three kinds of aspiration systems exist in phacoemulsification machines.
o
The peristaltic pump has rollers that move along tubing and create a relatively rapid
rise in vacuum.
o
The diaphragm pump has valves over both the inlet and outlet of a fluid chamber
covered by a diaphragm. This system allows a slower build of vacuum.
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o
Dhaval Patel MD
The Venturi pump produces the most rapid increase in vacuum. This, however, can
be the most dangerous because it allows almost instantaneous engagement of
unwanted tissues such as capsule or iris.

PMMA lenses, when packaged, may pick up static charges that attract dust and debris
when opened. Therefore, the lens may be rinsed with balanced salt solution before
insertion. Silicone lenses do not require this and, in fact, may be more difficult to handle
once they have gotten wet. Application of a viscoelastic, such as sodium hyaluronate, may
facilitate insertion of a lens, especially a foldable one, through a small incision.

IOL implantation is contraindicated in patients with juvenile rheumatoid arthritis-associated
iridocyclitis. Development of cyclitic membranes and subsequent ciliary body detachment
following extracapsular cataract extraction suggest the need for complete capsular
removal. Therefore, combined lensectomy and subtotal vitrectomy is recommended either
through the limbus or pars plana.
But recent data suggests that IOL can be implanted in JIA associated uveitis without
significantly affecting post operative uveitis incidence. (Foster’s Uveitis Book)

Lane and colleagues evaluated IOP elevation associated with three commonly used
viscoelastic agents (sodium hyaluronate, chondroitin sulfate, and hydroxymethylcellulose)
and all produced significant pressure elevations at 4 ± 1 hours postoperatively. Removing
the viscoelastic did not eliminate significant postoperative IOP elevation, although when
chondroitin sulfate was removed, the pressure elevation was slightly less.

The ciliary sulcus is only 0.83-mm posterior to the limbus vertically and 0.46-mm posterior
horizontally

The incidence of clinical cystoid macular edema is less than 1% following uncomplicated
cataract extraction. The incidence of angiographic evidence of cystoid macular edema is
approximately 10 times this.

Congential epicapsular pigment stars: its can be seen normally on anterior lens capsule.
They are remnants of the anterior tunica vasculosa.
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Systemic Investigations for subluxated lens:
o
Echocardiogram may show enlarged aortic roots or mitral valve prolapse in
Marian's syndrome.
o
High serum methionine is seen in homocystinuria.
o
Serum FTA-ABS for Syphilis as it is a known cause of ectopia lentis.
o
Urine thiosulphate is seen in sulphite oxidase deficiency, in which the disulphide
bond is disrupted and can cause ectopia lentis

Myotonic dystrophy: These patients have polychromatic cataract which is classically
described as "Christmas tree" cataract.

youngster with bilateral cataracts and epilepsy
Check Serum calcium. The disease is hypoparathyroidism or
psuedohypoparathyroidism.
Both these conditions are associated with epilepsy and bilateral cataracts and the blood
test shows a low serum calcium and a high serum phosphate. In the former condition the
parathyroid glands do not produce parathyroid hormone while in the latter, parathyroid
hormone is produced but the tissues especially the kidneys are resistant to its actions.
The two conditions can usually be differentiated by measuring the parathyroid hormone
concentration in the serum. They are both treated with calcium supplements and vitamin
D supplements.

What clinical condition leads to phimotic anterior capsule opening?
Pseudoexfoliation, because zonules can get stretched and your rhexis is made smaller
than you intended.

Singh signs for PPCD
o
A deep anterior chamber
o
White to chalky-white spots are produced, which are seen in front of and around the
posterior capsular defect.
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o
The capsule behind the opaque lens may show a partial or a complete white ringshaped opacity. This opacity is contained within the posterior cortex, while the
posterior capsule shows a hole with chalky-white spots on and around the defect.
o
Rarely, an opening in the posterior capsule shows pigment along the margins. Fine
dustlike pigment along with fine dense white opacities may be seen in the
Berger space. The presence of pigment suggests widespread movement of the fluid
beyond the posterior capsular defect.

Argentina flag sign: complication when performing capsulorrhexis in intumescent cataracts
stained with trypan blue

In diabetic cataract, hyperglycaemia results in myopia and vice versa.

Steroid induced cataract:
10 mg prednisolone/day for > 2 years can cause cataract.
100% incidence with 20 mg prednisolone/day > 4 year

Wrinkling of capsule at the start of capsulorrhexis is pathognomonic sign of inadequate
capsular support.

Membranous cataract is rare and may be associated with Hallermann–Streiff–François
syndrome. It occurs when the lenticular material partially or completely reabsorbs leaving
behind residual chalky-white lens matter sandwiched between the anterior and posterior
capsules.

Advantages of capsulorrhexis:
o
Traps the lens inside bag
o
Better control of surgery
o
ELP better
o
Resists tearing
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o
Dhaval Patel MD
PCO is decreased when overlap of IOL
Disadvantage of capsulorrhexis:
o
Phimosis
o
Sphincter effect leading to bag-IOL dislocation in PXF

Bryan Little‘s manouevre: capsule tear out and rescue manouere.

CRYSTALENS does not have UV bocking property.

The predominant yellow chromophores in the young human lens are metabolites of
tryptophan, especially N-formyl kynurenine glucoside.

Calib chop: preoperatively calculated the calibrated tip not only marks the entry point on
lens surface, it also measures as it reaches the desired depth when a vertical chop can be
effectively and safely executed called a calibchop.

The IDEM lens or the ―IDeal EMmetropia lens‖, was that IOL power which when implanted
within the eye restored emmetropic status after cataract surgery. The power of this lens was
mathematically deduced to be +17.0 D for an AC lens, +19.0D for an iris fixated lens and
+21.0D for a posterior chamber lens.

The Third and fourth generation IOL power calculation formulae incorporate a bit of both
theoretical and regression types which was called the ―Fudge factor‖ by duke elder.

The Haigis formula
o
4th generation formula which was an adaptation of the formula first suggested by
Gernet, Ostholt and Werner as early as 1970
o
also called the GOW 70 formula
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o
The versatility of the formula lies in the three individualized A constants namely a0,
a1 and a2.
o
The a0 is linked to the manufacturers lens constant.
o
The a1 is linked to the pre operative ultrasonically measured ACD (this has a default
value of 0.4).
o
a2 which is linked to the axial length measurements and which has a default value
of 0.1

Desmosomes of lens epithelial cells contain VIMENTIN whereas most epithelial cells in
the body contain cytokeratin.

Prechopping techniques:

o
Akahoshi technique: using special prechopper created by akahoshi
o
Preslice technique
o
Ultrachopper technique: Luis Escaf, ultrasonic knife that cuts the nuclear
substance
CDI = cohesion- dispersion index (%aspirated/mm Hg):
o
Cohesive OVDs: CDI >30
o
Dispersive OVDs: CDI <30

The patients who are left with < 1.0 D of astigmatism remain comfortable after surgery,
particularly if the astigmatism happens to be against the rule (ATR), as the patient will
experience increased depth of focus due to pseudoaccomodation.

With accumulation of the water-insoluble fraction of lens protein, a marked browning of
the lens nucleus occurs. The amount of accumulation correlates with the degree of
opacification.
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
Vitamin A does not have protective mechanism against oxidation in the lens.

LOCS III:

o
The LOCS III contains an expanded set of standards that were selected from the
Longitudinal Study of Cataract slide library at the Center for Clinical Cataract
Research, Boston, Mass.
o
It consists of six slit-lamp images for grading nuclear color (NC) and nuclear
opalescence (NO),
o
five retroillumination images for grading cortical cataract (C), and
o
five retroillumination images for grading posterior subcapsular (P) cataract.
o
Cataract severity is graded on a decimal scale, and the standards have regularly
spaced intervals on a decimal scale.
Persistant Pupillary Membrane PPMs:
o
PPMs are the remnants of a normal embryologic structure of the eye.
o
During fetal development they are continuous with the blood supply of the
developing lens.
o
The pupillary membrane begins to atrophy during fetal life, but atrophy may not be
complete until 4 to 8 weeks of age.
o
These strands are considered to be "persistent" when they do not regress by 8
weeks of age.
o
There are four variations of PPMs:
1. Iris to iris. The strand is attached to only iridal tissue, not touching the lens or
cornea.
2. One end attached to iris, the other not attached (free floating).
3. Iris to lens.
4. Iris to cornea.
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
Anterior and posterior ―Y‖ sutures are formed by FETAL nucleus and not EMBRYONIC
nucleus.

In posterior subcapsular cataracts, there is posterior migration of lens epithelial cells,
which swell along the posterior capsule. These swollen cells are called Wedl or bladder
cells.
In cortical cataracts, there is hydropic swelling of lens fibers. The eosinophilic, globular
material between lens fibers is called morgagnian globules.

Anterior polar cataracts are usually small and nonprogressive, do not usually impair vision,
and may be seen in association with microphthalmos, a persistent pupillary membrane, and
anterior lenticonus.
Posterior polar cataracts cause more visual impairment and tend to be larger than anterior
polar cataracts. Both can be autosomal dominant or sporadic. Posterior polar cataracts may
be associated with posterior lenticonus or a remnant of the tunica vasculosa lentis.

Raman spectroscopy is used for normal aging and pathologic processes in the lens.

LPR: Laser for Presbyopia Reversal

o
Ron Krueger who first investigated the effect of intralenticular femtosecond laser
surgery on accommodation
o
Rowiak Femtosecond Laser for Presbyopia Reversal
o
low-energy (2.0 μJ to 5.0 μJ per pulse) and high-frequency (100 kHz) infrared laser
(1040 nm).
o
The width of each single laser pulse is less than 400 femtoseconds.
o
The laser process is controlled by an integrated OCT imaging system. The laser is
able to cut 3-dimensional patterns with a working field diameter of up to 9.0 mm
within the crystalline lens. The presbyopia reversal cutting process is characterized
by an extremely low gas bubble production due to a low energy threshold.
FDA-Approved Accommodative Lenses
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


Dhaval Patel MD
o
Crystalens AT-45: The First FDA-Approved Accommodating IOL (Nov. 2003)
o
Crystalens 5-O (Nov. 2006)
o
Crystalens HD and AO
o
Not approved: Tetraflex
Dual-Optic Accommodative IOLs
o
Hara et al
o
Synchrony IOL
o
dual-optic, silicone, single-piece, foldable, accommodating IOL
o
5.5-mm high-plus powered anterior optic connected to a 6.0-mm variable negative
power optic by haptics that have a spring-like action
o
optical power of the anterior optic is +32.0 D
Types of Diffractive Multifocal IOLs
o
Alcon ReSTOR
o
Abbott Medical Optics Tecnis MF
o
Carl Zeiss Meditec AG Acri.Lisa 366D
o
Hanita SeeLens MF
o
Physiol IOL
o
FineVision IOL
o
Ari. Tec TwinSet
Zonal (Segmental) Refractive Multifocal IOLs
o
Lentis Mplus
o
Lenstec SBL-3
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
Trifocal IOLs
o
FineVision, Physiol; Belgium

o
25% hydrophilic acrylic IOL has, in addition to a near foci (+3.50 D), a foci for
intermediate vision (+1.75 D) to provide treated patients with a full range of
correction.
AT LISA tri 839MP, Zeiss; Germany


Dhaval Patel MD
(+3.33 D near add and +1.66 D intermediate add at the IOL plane
The pulsed electron avalanche knife (PEAK-fc, Carl Zeiss Meditec) is an electrosurgical
cutting device that allows precise "cold" and traction-free tissue dissection
The PEAK-fc appears to be a helpful cutting device for complicated cases of cataract
surgery, especially for mature and congenital cataracts.

Ultraviolet radiation-absorbing IOL
o
o
Two types of these compounds are commonly used in IOLs

Hydroxybenzophenones

Hydroxyphenylbenzotriazoles
Both absorb UV light energy and transform it into harmless heat energy (only a
fraction of a degree) by a process known as photoautomerism.

Statin users had a 9% increase in cataracts. (controversial)

Compared with no surgery, timely cataract surgery that improved the patient's vision was
associated with a 40% reduction in mortality risk.

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Glaucoma

Mucopolysachharides is glaucoma: 1,4,6

Eclipse Sign is seen in shallow AC.

Inspite of prophylactic PI, 15% will develop increase IOP.

Power of koeppe gonioscopy lens is +50D.

Evaluation of the CD ratio by ophthalmoscopy
use of the 5° aperture of the Welsh-Allyn ophthalmoscope (Gross‘ technique)
use of the grid (Hitchings‘ technique)

Sensitivity of automated Perimetry: (Quigley AJO 1997)
o
Loss of 5 db in sensitivity occurs when 20% of ganglion cells are gone from that
area.
o
Loss of 10 db is associated with loss of 40% of ganglion cells.
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TOP: Tendency Oriented Perimetry
o
For OCTOPUS, more popular in Europe.
o
Test each point once
o
Interpolate information to surrounding area
o
Highly correlated to standard octopus
o
4.1 minute for TOP vs 14.7 min for standard octopus
o
95% of points within 3 db of threshold
o
Defects tend to be wider and spread out

Ciliary body ablation should not be considered in NLP eyes because of the risk of
sympathetic ophthalmia.

Failure to relieve postoperative angle closure with iridotomy suggests malignant glaucoma,
which often responds to potent cycloplegics. If medical management fails, laser treatment
to open the anterior hyaloid face, or even pars plana vitrectomy, is necessary.

Imbert Fick‘s Low:
P = W/A
So W = P x A
Assumptions - object perfectly spherical, dry, perfectly flexible, and infinitely thin
Modified formula:
W+S = (PxA) + B
At A = 7.35 mm2 or the diameter of external corneal applanation = 3.06 mm, then S
=B
W= PxA (P=W/A)
W: external force
S: surface tension
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P: IOP
A: area of applanation
B: force needed to bend the cornea


Disinfection of applanation tips (immediately after use):
o
Thoroughly wipe with 70% isopropyl alcohol swab or 70% ethanol
o
Soak in 70% isopropyl alcohol solution for 5 minutes
o
Allow alcohol to evaporate or dry prism head to prevent corneal epithelial toxicity
o
Soak in a 1:10 sodium hypochlorite (household bleach) or 3% hydrogen peroxide
solution for 5 minutes. Follow by rinsing and drying to prevent damage to corneal
epithelium
Outflow facility = Rate of loss of aqueous per mm Hg of raised IOP per minute
Total outflow facility = C value = True outflow facility + Pseudo facility
C averages 0.28 microliters / min / mmHg (abnormal C < 0.20)

Topiramate (Topamax) is associated with acute secondary angle-closure glaucoma. Most
cases are bilateral, and can lead to blindness if not treated or recognized. Peripheral
iridectomy is ineffective for this type of angle-closure glaucoma.

Miotics cause a paradoxical rise in IOP in angle recession glaucoma due to reduction in
the uveoscleral outflow.

Vogt‘s sign: White anterior lens opacities (glaukomflecken) caused by ischemia of lens
epithelial cells from previous attacks of angle-closure

Range of HVF is 0.08 asb to 10000 asb. Decibel range is 0-51 db.
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Dhaval Patel MD
Aqueous humor production: 2-3 µl/min
Outflow facility in normal eyes ranges from 0.22 to 0.28 µL/min/mm Hg, and decreases with
age, ocular surgery, and trauma. Patients with glaucoma often have decreased outflow
facility.
Volume of Anterior Chamber: 250 microliters
Volume of Posterior Chamber: 60 microliters
Turnover of aqueous: 1.5 - 2 hours

Decreased aqueous humor formation with increased IOP (pseudofacility) has been
disputed by studies indicating that rate of aqueous formation is relatively pressureinsensitive (Shields, 1992).

Miotics lower intraocular pressure (IOP) by increasing trabecular outflow facility.
Cycloplegic agents, epinephrine, and prostaglandin analogs have been shown to increase
uveoscleral flow, whereas miotics decrease uveoscleral flow.

Koeppe gonioscopy is considered best for evaluating a patient with potential angle
recession because this system allows easier comparison of one eye with the fellow eye, or
one portion of the angle with another.

Scheie‘s line: Pigment on lens equator and posterior capsule in pigment dispersion
syndrome

Split fixation is the presence of visual field loss that comes close to fixation. A typical
pattern of progression is (i) loss near fixation (paracentral scotoma) to (ii) split fixation to (iii)
loss of fixation. Thus, the eye at greatest risk is not one with a 5-degree central field, but
one with the split-fixation in the horizontal meridian.

It is important to correlate changes in visual field with changes in the optic disc. The
following should raise suspicion about the diagnosis of glaucoma: (i) an optic disc that is
less cupped than would be expected for observed field loss, (ii) pallor of the disc that is
more impressive than the cupping, (iii) markedly asymmetric dyschromatopsia, or (iv)
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visual field defects uncharacteristic for glaucoma (e.g., respecting the vertical meridian).
A relative afferent pupillary defect (APD) can occur with glaucoma.

Pseudoglaucomatous optic nerve cupping, namely: (i) chiasmal compression, (ii)
arteritic anterior ischemic optic neuropathy (AAION), (iii) toxic optic neuropathies (such as
methanol toxicity), and (iv) hypotension (―shock‖ optic neuropathy).

The sine qua non of PDS is radial defects in the iris pigment epithelium.

The patient with very narrow angles and elevated pressure may have ―mixed mechanism‖
glaucoma with partial angle closure caused by pupillary block superimposed on open-angle
glaucoma. To determine if an angle-closure component is present, the effect of minimizing
pupillary block on intraocular pressure (IOP) must be determined. Cholinergic miotics
(pilocarpine) will cause miosis and lessen pupillary block and will also exert traction on the
trabecular meshwork (TM) and lower IOP by this unrelated mechanism. Thymoxamine, a
selective alpha-adrenergic antagonist, causes miosis and lessens pupillary block, without
affecting outflow facility. A decrease in pressure after thymoxamine (lessened pupillary
block) implies partial angle closure, and iridotomy is indicated. No change in IOP after
thymoxamine-induced miosis implies that an iridotomy may not be helpful.

Following heavy panretinal photocoagulation, choroidal effusion may cause anterior
rotation and swelling of the ciliary body resulting in closure of the angle.

In central retinal vein occlusion (CRVO), there may be transudation of serum into the
vitreous, driven by the elevated intravascular pressure. This hydration causes vitreous
swelling with subsequent secondary angle closure. There may also be ciliary body swelling
associated with CRVO.

Direct-acting miotics interact directly with the acetylcholine receptor, whereas indirect-acting
agents increase the activity of native acetylcholine at the synaptic junction (by blocking its
enzymatic degradation). Pilocarpine is a purely direct agent, whereas carbachol is felt to
exhibit both direct and indirect effects.
Miotics: indirect-acting agents-echothiophate, carbachol, demecarium.
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S/E: cataractogenesis, punctal stenosis, retinal tears and detachment.

The most common complication of both Nd:YAG and argon laser iridotomies is acute
glaucoma. Malignant glaucoma has been reported after a variety of seemingly benign
ocular laser procedures.

Posttrabeculectomy pain and decreased vision require evaluation for endophthalmitis,
malignant glaucoma, and suprachoroidal hemorrhage.

Short-term fluctuation (SF) and Corrected pattern standard deviation (CPSD) are not
available on SITA.

Central corneal thickness is increased in eyes with aniridia which may result in incorrect
measurement of IOP.

When performing laser trabeculoplasty a pigmented Schwalbe line should not be confused
with the posterior pigmented trabeculum. In laser trabeculoplasty it is important to identify
the scleral spur because the application of burns posterior to it will result in greater
inflammation, with consequent increased risk of early post-laser rise in IOP and the
formation of peripheral anterior synechiae.

A pupillary diameter of less than 3 mm can cause general depression of the field.

The Humphrey automated perimeter has a number of ways to test the reliability of the test
taker. A fixation loss occurs when the patient responds as if seeing a light when a target is
displayed in his blind spot. A false-negative response occurs when the patient fails to
respond to a suprathreshold stimulus at a location that would be expected to be seen. This
response may indicate a patient who is falling asleep or losing interest. Intermittently, the
perimeter will pause and the motorized light will change position, but no stimulus will be
presented. If the patient presses the button, a false-positive response is recorded. A
nervous or trigger-happy patient may have a high false-positive rate. Short-term
fluctuation describes the change in sensitivity when the same point is retested.
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
For the early detection of glaucomatous optic nerve damage, the most important
variable appears to be focal narrowing or notching of the neuro-retinal rim. Other
important variables are optic cup size in relation to optic disc size, disc asymmetry, and
presence of disc hemorrhages. However, disc hemorrhages can occur in other conditions
(e.g., anterior ischemic optic neuropathy [AION]) and disc asymmetry may be a normal
finding if the difference is slight (<0.2 difference).

Up to 50% of optic nerve axons can be lost before any change is detected on the
Goldmann visual field.

Ocular inflammation can lead to glaucoma via a variety of mechanisms including 1)
obstruction of the trabecular meshwork by inflammatory debris, 2) increased viscosity of
aqueous humor, 3) neovascularization, 4) uveal effusion, 5) pupillary block, and 6) formation
of peripheral anterior synechiae.

The common pathogenesis of glaucoma in the Sturge-Weber syndrome, thyroid eye
disease, and carotid-cavernous sinus fistula is an increase in episcleral venous
pressure through elevated venous outflow pressure or orbital congestion.

Corticosteroids are thought to raise IOP by lowering outflow facility perhaps due to an
accumulation of glycosaminoglycans in the trabecular meshwork.

Patients at particular risk for aqueous misdirection are those with crowded anterior
segments (i.e., angle closure, nanophthalmos). Postoperative inflammation may cause
swelling of the ciliary body and ciliary processes leading to aqueous misdirection.

Ocular side effects of pilocarpine include conjunctival vascular congestion, miosis,
induced myopia, cataract formation, and temporal or periorbital headaches. Rarely,
pilocarpine can be associated with retinal detachment. Pilocarpine does not cause
hyperopia.

Latanoprost and travoprost lower IOP by increasing uveoscleral outflow. (these 2 are
ProDrugs.)
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Bimatoprost decreases IOP by increasing uveoscleral and trabecular outflow.
Unoprostone appears to lower IOP by increasing trabecular outflow only.

Acute myopia is the only ocular reaction commonly associated with carbonic anhydrase
inhibitors.

The most frequent cause of failure after filtration surgery is bleb scarring due to episcleral
fibrosis.

In addition to inhibiting fibroblast proliferation, 5-FU also inhibits the growth of epithelial
cells of the conjunctiva and cornea. It is associated with several undesirable
complications including conjunctival wound leaks, corneal epithelial defects, thin-walled
ischemic blebs, hypotony, and suprachoroidal hemorrhage.

Laser trabeculoplasty effectively lowers IOP in patients with POAG, pigmentary glaucoma,
or pseudoexfoliation. It is ineffective and may actually worsen the IOP in eyes with
inflammatory glaucoma, recessed angles, or membranes in the angle, and in young patients
with developmental defects.

When treated with SLT, a primarily biologic response is induced in the trabecular
meshwork. This response involves the release of cytokines, which trigger macrophage
recruitment and other changes leading to IOP reduction. The laser beam bypasses
surrounding tissue, leaving it undamaged by light. This is why, unlike ALT, SLT is
repeatable several times. ALT patients can receive two treatments in a lifetime, whereas
SLT patients can receive two treatments a year. Even though SLT is a promising new
technology, further studies need to be done to prove that SLT is in fact better than ALT at
decreasing IOP pressure; at best, SLT is currently equivalent to ALT at reducing IOP.

In some cases, it may be advantageous to use both lasers: the argon for its coagulative
effects and the Nd:YAG for its disruptive properties.

The incidence of hypotony is highest with full-thickness procedures such as a posterior
lip sclerectomy. Because of this, these procedures are performed less commonly today.
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Partial thickness procedures, including trabeculectomies with antimetabolites, have lower
rates of hypotony. Setons are intermediate in incidence depending on the type of implant
and whether a ligature or other device is used to occlude the drainage tube.

Antifibrotic agents should be used with caution in young myopic patients due to the risk
of hypotony.

Modulation wound healing post glaucoma surgery
o
BAPN (beta-aminoproprionitrile), an inhibitor of lysyl oxidase, blocks collagen
cross-linking
o
5-FU inhibits fibroblast proliferation by acting selectively on the S phase of the
cell cycle
o
mitomycin-C is an alkylating agent that decreases DNA synthesis by causing
DNA cross-linking
o
Colchicine affects collagen cross-linking and thereby decreases scar formation.

Cyclodialysis clefts occur after traumatic injuries. Chronic hypotony usually results. These
clefts close spontaneously weeks to months later, usually resulting in a sudden increase in
the IOP. Usually, the trabecular outflow system will begin functioning more normally a short
period of time after the pressure spike has occurred.

In traumatic hyphema, Rebleeding is not an indication to operate unless elevated
pressure and corneal blood staining are threatened.

An intensely pigmented meshwork may be caused by pseudoexfoliation, pigment
dispersion syndrome, inflammation (uveitis), malignant melanoma, trauma, surgery, and
hyphema.

The Glaucoma Laser Trial study has demonstrated that ALT is a reasonable alternative to
medication (timolol) in the initial treatment of POAG. However, 2 years into the study, 56%
of laser-treated eyes needed supplemental medical therapy to control IOP. Laser-treated
eyes had a lower mean IOP.
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
In acute angle closure glaucoma, hydropic degeneration and impaired axoplasmic flow
cause swelling and hyperemia of the optic nerve.

Transscleral cyclophotocoagulation is useful in many types of refractory glaucoma,
such as glaucoma in aphakia or pseudophakia, neovascular glaucoma, glaucoma
associated with inflammation, and glaucoma in eyes with multiple failed filtering procedures.
Observations in animal and human eyes suggest that the most likely mechanism of IOPlowering is reduced aqueous production through destruction of ciliary epithelium.

If corneal astigmatism is greater than 3 D, IOP is underestimated for with-the-rule
astigmatism and overestimated for against-the-rule astigmatism.

Patients with POAG and relatives of POAG patients have a higher incidence of elevated
IOP in response to topical or systemic corticosteroids, but this is not a risk factor for
POAG; rather, it is a risk factor for steroid-induced secondary open angle glaucoma.

Ketamine and trichloroethylene can cause IOP to increase.

Thick cornea overestimates IOP & Thin cornea underestimates IOP.

Thick Mires overestimates IOP.

In Aqueous Humor, Only calcium and phosphorus are in concentrations of about one-half
that in plasma. Sodium, potassium, magnesium, iron, zinc, and copper all approximate
levels found in plasma. Chloride and bicarbonate vary from 20% to 30% above or below
plasma levels.

In lactating women, concentration of timolol in breast milk is higher than serum level.
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
Intercalary staphyloma occurs in absolute glaucoma. It is lined by root of the iris.

In infantile glaucoma, an affected parent has about a 5% chance of having a child with
infantile glaucoma, and the next subsequent sibling has approximately a 5% chance of
being affected.

Corneal clouding or tearing is more likely to be the presenting symptom in patients with
glaucoma in whom the onset is before the age of 3 months, whereas corneal enlargement
will probably be the presenting finding in older infants.

Unlike adults, pressures in children >20 mm Hg must raise a suspicion of glaucoma.

The 3 syndromes that comprise ICE have the common features of iris distortion, corneal
edema, and secondary angle-closure glaucoma due to angle endothelialization and
peripheral anterior synechiae formation. The specific findings of each syndrome are:
o
Iris nevus (Cogan-Reese) syndrome: flattening and effacement of the iris stroma,
pigmented iris nodules (pseudonevi) composed of normal iris cells that are bunched
up from the overlying membrane, corectopia, and ectropion uveae.
o
Chandler‘s syndrome: corneal edema often with normal IOP, and mild or no iris
changes (minimal corectopia, iris atrophy, peripheral anterior synechiae).
o
Essential iris atrophy (Progressive iris atrophy): proliferating endothelium
produces broad PAS, corectopia, ectropion uveae, and iris holes (stretch holes [area
away from maximal pull of endothelial membrane is stretched so thin that holes
develop] and melting holes [holes in areas without iris thinning due to iris ischemia]).

ICE is a unilateral, nonhereditary, progressive abnormality of the corneal endothelium that is
not associated with any systemic abnormalities. It most commonly affects middle-aged
women. Mesodermal dysgenesis is bilateral, congenital, and hereditary.

Mesodermal dysgenesis syndromes
o
Axenfeld‘s anomaly: posterior embryotoxon (anteriorly displaced Schwalbe‘s line)
with iris processes to the scleral spur. Glaucoma develops in 50%.
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o
Alagille‘s syndrome: Axenfeld‘s plus pigmentary retinopathy, corectopia,
esotropia, and systemic abnormalities (absent deep tendon reflexes, abnormal
facies, pulmonic valvular stenosis, peripheral arterial stenosis, biliary hypoplasia, and
skeletal abnormalities).
o
Rieger‘s anomaly: Axenfeld‘s plus iris hypoplasia with holes. Glaucoma develops in
50%.
o
Rieger‘s syndrome: Rieger‘s anomaly plus mental retardation and systemic
abnormalities (dental, craniofacial, genitourinary, and skeletal).
o
Peter‘s anomaly: central corneal leukoma (opacity due to defect in Descemet‘s
membrane with absence of endothelium) with iris adhesions, may have cataract and
develop glaucoma (50%), and is associated with cardiac, craniofacial, and skeletal
abnormalities. It is usually sporadic and bilateral (80%).
Riluzole and Lifarazine are neuroprotective as they inhibit the release of glutamate.
Memantine and Felbamate are neuroprotective as they block the NMDA receptors.

BAD and BAX genes: Stimulate retinal ganglion cell death
BCL-2 and BCL-Xl genes: Inhibits retinal ganglion cell death

Each 1 mmHg reduction in IOP leads to a 10% reduction in the rate of nerve fibre loss.

Rate of ganglion cell loss in normal population is approximately 5000/year.

Inferior PI is also known as Ando‘s PI.

MOST important medication to discontinue as far before glaucoma surgery as possible:
Echothiophate (causes breakdown of BAB) >> dipivefrine

Total internal reflection: Total internal reflection at the tear-air interface prevents a direct
view of the anterior chamber. To overcome this limitation, the critical angle must be
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increased for the tear-air interface by applying a plastic or glass goniolens to the surface.
Total internal reflection also occurs in fiberoptic tubes and indirect ophthalmoscopes.

Causes of VH after trabeculectomy
o
Haemorrhage from iridectomy which tracked itself into the vitreal cavity
o
During the iridectomy, the ciliary body was inadvertently cut resulting in vitreous
haemorrhage.

Ocular hypertension leads to ocular tissue damage, and hence to glaucoma, at an
incidence of about 1% per year.

Applanation Prism diameter: 3.06mm
Tonopen: 1.02mm
NCT: 3.6 mm
Dynamic Contour Tonometer – Pascal: The probe has a radius of curvature of 10.5 mm,
contact surface of 7 mm diameter and sensor diameter of 1.2 mm.

4-2-1 Rule of Glaucoma
The sensitivity of the visual field is by determining the threshold value at each point by the
bracketing technique (4-2 on the Humphrey and 4-2-1 on the Octopus perimeter). After
presenting a light stimulus the machine waits for a yes / no response. If the stimulus is not
seen, the intensity of the light seen is increased in steps of 4dB, till it is seen (machine
records this as supra threshold level). Subsequently, light stimuli are decreased in steps of
2dB till the stimulus is not seen (infra-threshold). Octopus perimeters make one more
movement in steps of 1dB. The actual threshold is between the supra-threshold and infra
threshold.

Systemic evaluation of the neonate with glaucoma: urinalysis for proteinuria and
aminoaciduria.(LOWE‘S SYNDROME)

antiarthritis agents to increases in intraocular pressure  Glucosamine
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
Aqueous flow, outflow facility, and episcleral venous pressure are thus the primary
determinants of IOP. In the eye, the driving pressure for aqueous outflow equals the
difference between intraocular pressure (IOP) and episcleral venous pressure (Ve). The
outflow facility is the reciprocal of resistance.

Uveoscleral outflow is pressure-independent.10-50% of total outflow.

Cycloplegic agents, epinephrine, and prostaglandin analogs have been shown to
increase uveoscleral flow, whereas miotics decrease uveoscleral flow.

Episcleral venous pressure: 8 to 12 mm Hg.

Applanation measurements are essentially independent of ocular rigidity.

Digital pressure on a Goldmann lens  may tend to narrow the angle.
Zeiss lens  opens angle

Blood may enter Schlemm's canal when episcleral venous pressure exceeds intraocular
pressure (IOP). It occurs in carotid-cavernous fistula, severe thyroid eye disease, excessive
digital pressure on a Goldmann gonioscopic lens, ocular hypotony.

If a patient has glaucomatous visual field-type defects, corresponding optic nerve head
abnormalities should exist.

high risk factors for ultimate damage to the optic nerve:
elevated IOP, positive family history of glaucoma, myopia, diabetes mellitus, cardiovascular
disease, race (i.e., African American), asymmetric cupping, large cups, and early
nonspecific visual field changes.
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
the situation that may be the one most frequently misdiagnosed as ―normal-tension‖
glaucoma is primary open-angle glaucoma (POAG) in which intraocular pressure (IOP)
fluctuations have obscured the actual nature of the disease. In addition, there are other
disorders that can feature pseudoglaucomatous optic nerve cupping, namely: (i)
chiasmal compression, (ii) arteritic anterior ischemic optic neuropathy (AAION), (iii) toxic
optic neuropathies (such as methanol toxicity), and (iv) hypotension (―shock‖ optic
neuropathy).

pigmentary glaucoma: The sine qua non of this condition is radial defects in the iris
pigment epithelium. Pigmentary glaucoma usually occurs in young myopic men, typically in
their third or fourth decade of life. For obscure reasons, women with the disease tend to be
older than men. Exercise or pupillary movements may induce a shower of iris pigment
release, with resultant increased intraocular pressure (IOP).

In hemolytic glaucoma, hemoglobin-laden macrophages block the trabecular meshwork
(TM), whereas in ghost cell glaucoma, rigid, degenerated khaki-colored red blood cells
from the vitreous enter the anterior chamber and obstruct the TM. Hemolytic glaucoma may
occur within days of hemorrhage, whereas ghost cell glaucoma is seen weeks to months
later.

Both mydriatics and miotics can precipitate angle-closure in eyes with shallow anterior
chambers. This is true for both topical medications and systemic drugs that affect the pupil.
Examples include antihistamines, which can have anticholinergic activity.

narrow anterior chamber angles and normal IOP  DRPPT (most predictive but no
prospective study yet), darkness will induce pupillary dilation, and prone positioning will
move the lens forward.
narrow anterior chamber angles and elevated IOP  thymoxamine test. Patients may
have “mixed mechanism” glaucoma with partial angle closure caused by pupillary block
superimposed on open-angle glaucoma. To determine if an angle-closure component is
present, the effect of minimizing pupillary block on intraocular pressure (IOP) must be
determined. Cholinergic miotics (pilocarpine) will cause miosis and lessen pupillary block
and will also exert traction on the trabecular meshwork (TM) and lower IOP by this unrelated
mechanism. Thymoxamine, a selective alpha-adrenergic antagonist, causes miosis
and lessens pupillary block, without affecting outflow facility. A decrease in pressure
after thymoxamine (lessened pupillary block) implies partial angle closure, and iridotomy is
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indicated. No change in IOP after thymoxamine-induced miosis implies that an iridotomy
may not be helpful.


suspicion of plateau iris if:
o
deep anterior chamber centrally.
o
a young patient with myopia.
o
a flat iris plane.
Contraindicated in paroxysmal tachycardia  epinephrine, dipivefrin, propine
Contraindicated in depression/ psychiatric illness  timolol, acetazolamide
Caution in a patient with narrow angles  epinephrine, apraclonidine (due to mydriatic
action)

The blood-aqueous barrier allows formation of the gradient necessary to draw fluid from
the vitreous. Interruption of this gradient as in inflammation decreases the effectiveness
and duration of osmotic effects.

Mannitol is distributed only in the blood compartment, whereas urea moves freely in total
body water, so mannitol is more effective.

Argon laser trabeculoplasty (ALT)
o
Response appears to be better for pigmentary glaucoma and pseudoexfoliation
and poorer for inflammatory diseases, recessed angles, membranes in angles,
young patients with developmental defects, and aphakic eyes.
o
It is applied to the anterior half of the trabecular meshwork. Application of laser to
the posterior half risks the development of anterior synechiae.
o
The effect on pressure reduction depends on the pre-treatment pressure, age of the
patient and type of glaucoma.
o
It is less effective in pseudophakic and aphakic patients. The effect of pressure
reduction tends to decrease with time and retreatment tends to be less effective.
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
The Tonopen appears to have more accurate pressure readings in patients after laserassisted in situ keratomileusis (LASIK) surgery. Goldmann readings can be artificially low
after LASIK.

Topiramate (Topamax) is associated with acute secondary angle-closure glaucoma.
Most cases are bilateral, and can lead to blindness if not treated or recognized. All of the
findings are reversible if recognized early and the drug is discontinued. Peripheral
iridectomy is ineffective for this type of angle-closure glaucoma.

Generally, uncomplicated cataract surgery (Phaco/PCIOL) lowers intraocular pressure
(IOP) by 1 to 2 mm Hg.

Iridencleisis: Historical procedure, from observation that that inadvertently incarcerated iris
in the wound after intracapsular cataract extraction or surgical iridectomy sometimes
resulted in IOP lowering

Frequency-doubling technology, FDT
o
targets the magnocellular ganglion cells, which are damaged early on in the course
of glaucoma. It does this by utilizing the illusion of frequency doubling produced by a
low spatial frequency grating undergoing high temporal frequency reversal.
o
It is much quicker and easier to perform than conventional automated perimetry

The anterior border of the trabecular meshwork is defined by Schwalbe's line and the
scleral spur defines the posterior border.

The anatomical limbus is defined by Schwalbe's line.

Pilocarpine increases the aqueous outflow through the trabecular meshwork and therefore
is ineffective in the presence of raised episcleral pressure like SWS.
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Iris transillumination defects:
PDS: near pupillary margin (you can remember this by margin is most pigmented which
is lost in PDS)
PXF: at midperipheral iris

Blitz anesthesia: combined anterior sub-Tenon's, topical, and intracameral ("Blitz")
anesthesia used for surgery at Wills Eye Institute.

Incidence of aniridia in patients with Wilms' tumor is 1/73 (1.4%)
Incidence of Wilms' tumor in sporadic aniridia is 34%

Boussinesq model of natural convection in the human eye and the formation of
Krukenberg's spindle: When paths of pigment particles are calculated based on the
predicted flow field, the particles circulate throughout the anterior chamber but tend to be
near the vertical centerline of the eye for a greatest period of time. Further, the particles are
usually in close proximity to the cornea only when they are near the vertical centerline. We
conclude that the convective flow pattern of aqueous humor is consistent with a vertical
pigment spindle.

STAR Calculator:
o Scoring Tool for Assessing Risk
o Dr Mederios, Dr Weinreb and colleagues at Hamilton glaucoma center
o to calculate the likelihood to conversion to glaucoma from ocular hypertension based
on the 6 risk factors identified by OHTS

Causes of false field defects
o
Ptosis and dermatochalasis
o
tilted optic disc
o
small pupil
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o
rim of the trial lens
o
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
Ghost cells represent hemolyzed red blood cells and not Hemosiderin-laden macrophages.

Pathways Served by Retinal Ganglion Cells
o
o
o
ParvoCellular

Midget ganglion cells

Small field

High spatial resolution

Conveys information regarding red green opponency

Static firing system

Ring/High pass resolution Perimetry (HPRP) tests this system
Magnocellular

Parasol ganglion cells

Large field

Low spatial resolution

Conveys information regarding motion

Tonic firing system

Frequency doubling Perimetry (FDP) tests this system
KonioCellular

Bistratified ganglion cells

Large field

Low spatial resolution

Conveys information regarding blue yellow opponency

Short wavelength Automated Perimetry (SWAP) tests this system
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
Swap USES size V stimulus.

Some of the new-technology IOLs have a yellow filter which may conceivably
interfere with blue on yellow perimetry, also known as short wavelength
automated perimetry (SWAP). A recent study confirmed there was no
interference by the yellow filter in the IOL as determined by SWAP.

1 mmHg increase in episcleral venous pressure increases IOP by 0.8 mmHg.

Co-efficient of ocular rigidity K = 0.0215

Prostaglandin analogs such as latanoprost (Xalatan) more commonly produce conjunctival
hyperemia than true allergic conjunctivitis. From 1% to 5% of patients taking dorzolamide
(Trusopt) may have allergic symptoms. Up to 20% of patients taking brimonidine
(Alphagan) may show such symptoms.

The continuous-wave argon laser was the unit most commonly used for creating
iridotomies in the early days of laser surgery; however, the pulsed Nd:YAG laser is
probably the more commonly used today.
Iridotomies created with an argon laser have more extensive early edema and tissue
destruction at the margins of treatment histologically as compared with those created with
the Nd:YAG laser. Argon laser has the disadvantage of more iritis, pupillary distortion,
and late closure of the iridotomy.
Clinically, the Nd:YAG laser has the disadvantage of frequent bleeding. In general, Nd:YAG
laser iridotomies require fewer total applications with a marked reduction in total energy as
compared with argon laser iridotomies. In some cases, it may be advantageous to use both
lasers: the argon for its coagulative effects and the Nd:YAG for its disruptive properties.

Colchicine affects collagen cross-linking and thereby decreases scar formation.

Patients with Fuchs' heterochromic iridocyclitis typically have abnormal vessels present
in the angle without peripheral anterior syndrome (PAS), but they do not have a
hyperpigmented meshwork.
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
Isolated depressed quadrantic defects result if the patient misses the early portion of the
test in which the machine attempts to determine the threshold for each quadrant.

A tube shunt can be placed in the presence of a scleral buckle. In post vitrectomy cases, the
tube can be placed through the pars plana.

GDx VCC is not useful in patients with associated macular pathology like ARMD.

Trabectome
o
Ab-Interno Trabeculotomy
o
trabecular bypass device that re-establishes the natural outflow passageway,
allowing aqueous to drain directly into the Schlemm canal from the anterior chamber
o
The ablation of trabecular meshwork and inner wall of the Schlemm canal create a
cleft that is theoretically less prone to fibrosis than goniotomy or trabeculotomy
o
FDA approved in 2006

chromatic visualevoked potential (VEP), which utilizes red-green flicker, was found to be
altered in nonglaucomatous optic neuropathies, but not in glaucomatous optic neuropathies.

Diabetes has not yet been shown to increase the incidence of glaucoma. Although the
weight of available evidence suggests that diabetes is probably a risk factor for glaucoma,
this has not been a consistent finding. Self- reported diabetes was associated with COAG
progression in the AGIS and the CIGTS (Collaborative Initial Glaucoma Treatment Study)
but not in the CNTGS or the EMGT.

CB1: Increases outflow
CB2: decreases production
The CB1 receptor is present in the ciliary body of rat and human.
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Glaucoma vaccines under development
o
glatiramer acetate (Cop-1)
o
brimonidine
o
MK-801, which is an NMDA receptor antagonist

In a multicenter British study of trabeculectomy, retrospective, cross-sectional study found
the total incidence of shallow or flat anterior chambers to be 0.9%, and the incidence of
hypotony maculopathy was less than 1%, compared with 10% and 4%, respectively, in
the Tube vs Trabeculectomy Study.

Patients with sleep apnea were 1.67 times more likely to develop glaucoma than patients
without apnea

Women who have used oral contraceptives for 3 years or more and who have additional
risk factors for glaucoma should be checked annually for the disease during their eye exams
as OCPs doubled their risk for glaucoma.

Retina

In CME, The fluid is accumulated between the outer plexiform layer and the inner
nuclear layer.

The organised vitreous haemonhage blood is called Ochre membrane.
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
Retina has no sensitivity to pain and sensitivity of retina is limited to light generally, that‘s
why any flashes or sudden shower of floaters becomes significant.

Elschnig spots: focal choroidal infarcts in HTN retinopathy

Siegrist streaks: Linear chain of hyperpigmented spots over sclerosed choroidal vessel in
chronic hypertension or choroiditis

CRAO: 20% emboli, rest thrombi, mechanical, vasculitis, trauma
BRAO: 90% Emboli, rest intraocular inflammations such as toxoplasmosis or herpes retinitis
(the acute retinal necrosis syndrome) can lead to BRAO.

Henle‘s layer: OPL, Obliquely oriented cone fibers in fovea

Flame-shaped hemorrhages and cotton-wool spots are ophthalmoscopic changes
indicative of acute, severe hypertension. When these features occur in the absence of
arteriolar sclerotic changes (i.e., AV crossing phenomenon), the hypertension is most likely
of recent onset.
In such cases, hypertension may be associated with renal insufficiency, encephalopathy,
and impairment of cardiac function. Controlled reduction of blood pressure should be
initiated immediately.

van Trigt‘s sign: Venous pulsations on optic disc (normal finding)

Autofluorescence is produced when certain tissues/material are stimulated with
monochromatic blue light and emit in the yellow-green range, as fluorescein does. The two
optic nerve lesions that may autofluoresce are astrocytic hamartomas and drusen. Large
accumulations of lipofuscin (i.e drusens) also may autofluoresce. To demonstrate this,
fundus photographs should be obtained through the standard fluorescein setup, but without
fluorescein injection. Lesions will appear bright, as if they had absorbed fluorescein,
although none was injected. Note that this is not the same as a “red-free” photograph
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(which is produced with a green filter that does not provide sufficient blue light to
stimulate autofluorescence).
On the other hand, pseudo-autofluorescence results from reflection of light from lightcoloured or white fundal structures such as myelinated nerve fibres, sclera, hard
exudates or cotton wool spots.

Nodular (hard) drusen consist of a focal thickening of the basement membrane of the
retinal pigment epithelium. Clinically, they appear as small yellow or yellow-white spots
measuring 50 µm in diameter.
Soft (exudative, fluffy) drusen are bigger and appear less dense and fluffier
Basal laminar deposits consist of banded basement membrane material (wide-spaced
collagen) located between the basal plasmalemma of the retinal pigment epithelium and its
basement membrane.
Basal linear deposits refer to material located external to the basement membrane of the
retinal pigment epithelium.

The characteristic ocular lesion of angiomatosis retinae, or von Hippel's disease, is a
retinal angioblastoma. This is a retinal capillary hemangioma (hemangioblastoma).
The cavernous hemangioma of the retina is a rare lesion that can be associated with
similar skin and central nervous system (CNS) lesions.
Diffuse choroidal hemangiomas (tomato ketchup fundus) are associated with SturgeWeber syndrome (encephalofacial angiomatosis).

White lines of Vogt: Sheathed or sclerosed vessels seen in lattice degeneration

The etiology of Coats' disease is unknown, and there does not appear to be any genetic,
familial, racial, or ethnic predisposition. However, Coats'-type retinal vascular changes have
been noted in patients with facioscapulohumeral muscular dystrophy, Turner's syndrome,
Senior-Loken syndrome, and one variant of the epidermal nevus syndrome. In addition,
Coats'-like retinopathy has been noted in up to 3.6% of patients with retinitis pigmentosa.
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
The retinopathy of Alport's syndrome is generally mild and nonprogressive and resembles
fundus albipunctatus clinically.

Although angiographically detectable cystoid macular edema (CME) is present in 10% to
20% of patients following extracapsular surgery, visual loss only occurs in 1% to 2%. For
intracapsular surgery, the percentages are 40% to 60% and 2% to 10%, respectively.

Klein‘s tags: Yellow spots at base of macular hole

CSME is defined as one or more of the following criteria:
1. Retinal thickening within 500 µm of the fovea.
2. Hard exudates within 500 µm of the fovea with associated retinal thickening.
3. Retinal thickening 1 disc area or greater, part of which is within 1 disc diameter of
the fovea.


DME
o
Diabetic macular edema apparently: No apparent retinal thickening or hard
exudates absent in posterior pole
o
Diabetic macular edema apparently: Some apparent retinal thickening or hard
exudates present in posterior pole

Mild diabetic macular edema: Some retinal thickening or hard exudates in
posterior pole but distant from the center of the macula

Moderate diabetic macular edema: Retinal thickening or hard exudates
approaching the center of the macula but not involving the center

Severe diabetic macular edema: Retinal thickening or hard exudates
involving the center of the macula
Medical Risk Factors for Progression of Diabetic Retinopathy
o
Hyperglycemia
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Hypertension
o
Hyperlipidemia
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
A chorioretinal rupture and necrosis is known as sclopetaria.

Paton‘s sign: Conjunctival microaneurysms in sickle cell disease

Paton‘s lines: Circumferential peripapillary retinal folds due to optic nerve edema

Foveal hypoplasia has been associated with aniridia and albinism.

The radiating fibers of Henle in the outer plexiform layer lead to the cystic spaces in
CME.

POHS is thought to be more prevalent in the Ohio-Mississippi river valley than in the rest
of the United States. The San Joaquin valley has been linked to coccidiomycosis, and
the Rocky Mountains have been linked with Lyme disease or Rocky Mountain spotted
fever.

Approximately 10% of patients with dry ARMD will progress onto the wet form.

In contrast to Vogt-Koyanagi-Harada disease, the choriocapillaris is uninvolved with the
inflammation in sympathetic ophthalmia.
??One of the classic findings in both sympathetic ophthalmia and the Vogt–Koyanagi–
Harada syndrome is the preservation of the choriocapillaris.

Conditions that may have CME without leakage of fluorescein include Goldmann-Favre,
retinitis pigmentosa, and nicotinic acid maculopathy. Epiretinal membranes may cause
a CME that leaks from traction and distortion of paramacular capillaries.
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Goldmann–Favre vitreoretinal degeneration is an autosomal recessive condition
characterized by a combination of night blindness, cataract, optically empty vitreous cavity,
peripheral pigmentary retinal changes, peripheral and macular retinoschisis, lattice
degeneration, and characteristic changes on electroretinography.

Depression sign of Goldberg: Focal loss of nerve fiber layer after resolution of cotton-wool
spot

In patients with higher degrees of myopia, more substantial fundus changes may occur. The
enlarged temporal crescent's width may exceed one third of a disc diameter. A crescent light
finding known as the Weiss-Otto reflex may become apparent on the nasal aspect of the
disc. This reflex results from concentric ―piling up‖ of the nasal retina and choroid, and it is
best appreciated in young persons.

True silent choroid is defined as the blockage of underlying choroidal fluorescence during
fluorescein angiography by material in the RPE cells. This occurs classically in patients who
have Stargardt's disease. Lipofuscin accumulation within RPE cells results in the blockage
of underlying choroidal fluorescence and gives the appearance of a very dark or silent
choroid. Systemic argyrosis, which occurs in patients who are receiving systemic silver
(e.g., from tanning agents), can also cause an angiographically dark choroid.

In a patient without a vitreous hemorrhage, the argon laser allows the placement of excellent
laser burns. The wavelength of krypton red (647 nm) is best able to penetrate vitreous
hemorrhages and deliver the energy necessary to create photocoagulation scars. This laser
also penetrates nuclear sclerotic cataracts better than the argon. The xenon arc emits a
large spectrum of wavelengths and has been replaced with the monochromatic lasers. The
CO2 laser is well-absorbed by water and is used for surface tissue ablation.

Commotio represents an actual disruption or destruction of retinal photoreceptor
elements and photoreceptor cells in the outer layers of the retina. It does not represent
retinal edema.
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The most common traumatic retinal tear is an inferotemporal retinal dialysis. The vast
majority of retinal dialyses occur in this quadrant. After trauma, the most common retinal tear
is inferotemporal dialysis, followed by giant tears, flap tears, and tears around lattice. These
statistics are true only for blunt ocular injury.

Fluorescein leakage is not a feature of either solar maculopathy or photic injury. Both
may be associated with intense staining of the damaged RPE, particularly in the acute
phases of the injury. As the injured RPE heals, the fluorescein angiogram would be
characterized by persistent window defects.

White-centered hemorrhages can be found in conditions with septic emboli (endocarditis,
Candida bacteremia), leukemia, and collagen-vascular diseases.

Fluorescein angiography of APMPPE is characterized by early hypofluorescence of
lesions, followed by late hyperfluorescence of the entire lesion.

Fluorescein angiography in MEWDS is characterized by early punctate
hyperfluorescence, often in a wreath-like configuration, followed by late staining of the
same punctate areas of hyperfluorescence. These areas of hyperfluorescence correspond
to the white spots seen clinically. Late disc staining is also a common feature.

Adult onset foveomacular vitelliform dystrophy is not associated with an abnormal
EOG.

Juvenile X-linked retinoschisis typically is associated with schisis at the level of the nerve
fiber layer. (spoke wheel pattern)
Reticular retinoschisis is characterized by an involutional splitting of the retina in the
nerve fiber layer.
Involutional retinoschisis has splitting at the outer plexiform layer.
Because the photoreceptors are unaffected, the a-wave on the ERG is intact, but both the
scotopic and photopic b-waves are reduced in proportion to the amount of retinal schisis.
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The EOG and dark adaptation test are normal or abnormal depending on the stage of
disease.
The macula is involved early, showing microcysts and radiating retinal folds, but fluorescein
angiography exhibits no leakage.
Perimetry may also be helpful in the differential diagnosis of retinoschisis. Relatively flat
retinoschisis can be readily differentiated from shallow retinal detachment in that the former
invariably causes an absolute field defect, while the latter causes only a relative defect.
Perimetry is less specific for bullous detachment, because an absolute field defect could be
found in either detachment or retinoschisis.

Oguchi's disease is an X-linked recessive form of congenital stationary night blindness. It is
associated with the Mizuo-Nakamura phenomenon, which is the appearance of a golden
brown fundus in the light adapted state with a normalization of the color of the fundus on
dark adaptation.

Gyrate atrophy is a metabolic disorder that is associated with a deficiency in the ornithine
aminotransferase enzyme, critical in the urea cycle.

Surface tension of silicone oil is significantly less than the surface tension of all gases,
including air.

Ganglion cells do not contribute to the ERG response. The ERG may be normal in the
presence of total disc cupping.
The negative a-wave (late receptor potential) originates in the photoreceptors.
The positive b-wave originates in the bipolar cell layer, probably in response to increased
potassium concentration in the extracellular space of the bipolar cells.
The positive c-wave appears to originate from the RPE.

Ocular structures that autofluoresce include the corneal epithelium and endothelium, lens,
macular and RPE pigments, optic nerve drusen, and RPE deposits in Best disease.
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
Partial PVD, detected with OCT has been shown to start perifoveally and progressively
detach in stages, leaving the foveal and the optic nerve attachment to separate last.

Flashes of light that appear as jagged lines or ―heat waves‖• often lasting 10 to 20 min
and present in both eyes, are more likely to be a migraine. These fortification lines may or
may not be followed by a headache. Visual function returns to its premigraine baseline.

development of choroidal effusion following panretinal photocoagulation: short axial
length (<23 mm)

ETDRS found that twice as many untreated patients lost vision. It is not accurate to
conclude that laser treatment is likely to improve vision in diabetic macular edema.

The degree of pigmentation observed ophthalmoscopically in any human fundus
depends on the number of pigmented melanocytes in the choroid. Retinal pigment
epithelium (RPE) pigmentation contributes to a lesser degree.

Rods and cones are characterized by three components:
the synaptic body, the inner segment, and the outer segment.
The synaptic body of a rod is called a spherule, whereas that of the cone is called a
pedicle.
Photopigment is stored in discs in the outer segments. In rods, the discs are not attached to
the cell membrane, but cone discs are continuous with it.

Intraretinal processing occurs from photoreceptors to bipolar cells to ganglion cells, with
modulation by horizontal (outer plexiform layer) and amacrine (inner plexiform layer) cells.

A cilioretinal artery contributes to the vascular supply of the retina in approximately 50% of
individuals and 30% of eyes. In 15% of individuals, it contributes to macular circulation.
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
Normally, axons of ganglion cells do not become myelinated until after they pass through
lamina cribrosa, as part of the intraorbital optic nerve. When myelinated fibers are visible
ophthalmoscopically, oligodendrocytes have migrated anteriorly.

Multiple Branch retinal artery occlusion  suspect Susac's syndrome.

The results of the EVS study indicated the following:
1. There was no difference in final visual acuity/media clarity whether or not patients
received systemic antibiotics.
2. Hand motions or better visual acuity on presentation did equally well with immediate
vitreous biopsy or vitrectomy.
3. Eyes with light perception-only vision had much better visual outcome with immediate
vitrectomy rather than vitreous biopsy.

RPE degenerations have been identified in patients with Hunter's, Hurler's, Sanfilippo's,
and Scheie's mucopolysaccharidoses. Maroteaux-Lamy syndrome is not usually
associated with RPE degeneration.

Rhegmatogenous detachments occur in up to 25% of patients with CMV retinitis. They
are associated with a diffusely necrotic peripheral retina with numerous small retinal holes.

RPE cells comprise the outer blood-retinal barrier; the inner blood-retinal barrier consists of
the endothelium lining the retinal blood vessels.

The retina is attached at the ora serrata and the optic nerve. The uvea has attachments at
the optic nerve, scleral spur, vortex veins, and long and short posterior ciliary vessels. This
anatomic difference helps to separate choroidal detachments from retinal detachments on
ultrasonography.

Among the causes of decreased concentration of hyaluronate in vitreous are syneresis,
myopia, aphakia, diabetes mellitus, and injury with hemorrhage, inflammation, or surgery.
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
Each photoreceptor renews its outer segment every 10 days.

The ATP-dependent Na+-K+ pump can be found on the Apical surface of the RPE cell.

The rods are 100 to 1000 times more sensitive to light than the cones, allowing better
vision in dim light. The highest concentration of rods is actually 20° from the fovea.

Most consistent finding in RP is  reduced ERG response

Best disease is disorder of RPE.

The 4 characteristic findings of POHS are:

o
punched-out chorioretinal lesions (histo-spots)
o
peripapillary atrophic pigmentary changes
o
lack of vitritis
o
CNV
Doses >3 mg/kg/day or 300 g total of chloroquine, and >6.5 mg/kg/day (<400 mg/day
appears safe) or 700 g total of hydroxychloroquine may produce the bull‘s eye
maculopathy. The total daily dose seems more critical than the total cumulative dose.
The maculopathy often progresses after medications are discontinued because the drug
concentrates in the eye. Hydroxychloroquine appears safer since it does not readily cross
the blood–retinal barrier (toxicity rarely occurs with use <7 years).
Check visual acuity, red Amsler grid and visual fields (central 10 with red test object)
at baseline and every 6 months (chloroquine) or 12 months hydroxychloroquine) while
patient is taking medications; color fundus photographs (especially if abnormalities seen)
and color vision (preferably including the blue-yellow axis) are optionally checked.
The two most sensitive tests for detecting these defects are the Adams Desaturation15 test and the Hardy-Rand-Rittler test.
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High risk patients with drug use >5 years with high fat level body habitus, renal or liver
disease, and age >60 years old especially if frail or extremely thin are at higher risk of
developing toxicity and should be checked more frequently.
Low-risk patients (defined as nonobese individuals under age 60 years old, using less than
3 mg/kg/day of chloroquine or 6.5 mg/kg/day of hydroxychloroquine for fewer than 5 years,
and without concomitant renal, hepatic, or retinal disease) require no additional screening
evaluations.

Chronic vitreous cells are likely to be absent in Ocular Histoplasmosis.

Ocular inflammatory disease most commonly associated with multiple sclerosis is
Intermediate Uveitis.

Most common cause of vision loss in ARMD is fibrous scarring. (not CNVM ??)

Leopard-spot pigmentation may appear in systemic large cell lymphoma, leukemia,
bilateral uveal melanocytic proliferation, and organ transplant chorioretinopathy

Origin of the myopic crescent. As the eye enlarges, the choroid and retina gradually pull
away from the temporal optic nerve head. Thus, in extreme cases, sclera is seen. In less
extreme enlargement, choroid or a rim of pigment epithelium can be seen.

Patients with soft drusen are more likely to develop choroidal neovascular membrane.

A longitudinal study including 447,407 people with diabetes but without macular edema
found that diabetic neuropathy (hazard ratio [HR], 1.59) was second only to type 1
diabetes in predicting which patients would progress to macular edema. Diabetic
nephropathy had an HR of 1.41, Latino race had an HR of 1.28, and black race had an HR
of 1.14.
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
AREDS2 found a 5-year rate of progression to age-related macular degeneration (AMD) of
31% for patients receiving placebo. No significant difference in rate of progression to
AMD was seen among these groups: antioxidants (rate of 29%), omega-3 fatty acids (31%),
both (30%).

An analysis of AREDS found that, compared with those without AMD, the odds of death
associated with circulatory disease in men with advanced AMD was about 2 times
greater.

AREDS found that high-dose antioxidants protect against AMD. A new analysis of data
from the AREDS population found that high-dose antioxidants do not affect intraocular
pressure.

study of AMD in Wisconsin found 512 incident cases of early AMD and 117 incident cases
of late AMD. The routine use of aspirin 10 years before the study was significantly
associated with the incidence of late AMD. The estimated incidence was 1.76% in those
who regularly used aspirin and 1.03% in nonusers. Early AMD was not significantly
associated with aspirin use.

myopic patients with diabetes may be up to 60% less likely to develop diabetic
retinopathy than patients without myopia.

Myopia >2D is protective for DR.

Aldose reductase gene mutation causes more susceptibility of type 2 DR patients for
developing retinopathy.

In all, 13.4% of the patients receiving ocriplasmin and 3.7% of the placebo group achieved
nonsurgical resolution of vitreomacular adhesion at day 28. intravitreal injection of
ocriplasmin (125 µg).
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
IOFB with >90% copper generally cause an acute inflammatory response (including
intraocular necrosis), concentrations of 70% to 90% cause chalcosis leading to a copper
ring (identical to the Kayser-Fleischer ring in Wilson's disease) and sunflower cataract.
Concentrations <70% can be tolerated; however, other factors such as location and fibrous
encapsulation modulate the tissue reaction.

general immune response, similar to what is seen in onchocercisis (Mazzoti reaction) or in
some cases of syphilis (Herxheimer reaction)

Gunn‘s dots: Light reflections from internal limiting membrane around disc and macula

Gunn‘s sign: Arteriovenous nicking in hypertensive retinopathy

22% of eyes had vitreous detachment by age 65. This number increased to 60% by age 75.

Retinal attachment:
1. negative pressure in the subretinal space created by the metabolic pump of the retinal
pigment epithelium and
2. the relatively higher oncotic pressure in the choroid,
3. interdigitation of the pigment epithelial cell processes and the outer segment of
photoreceptors, and
4. mucopolysaccharide ―glue‖ between the pigment epithelium and the sensory retina

Retinoschisis is frequently accompanied by atrophic holes. Inner-layer holes are generally
small and difficult to see. Outer-layer holes, which are larger and therefore more easily seen,
are much more significant in the pathogenesis of retinal detachment.

A retinal dialysis is a circumferential linear tear, the anterior margin of which is at or near the
ora serrata. The retina is thinnest and least developed at the ora, especially in the inferior
temporal quadrant. Dialyses occur at any age, but they are particularly common in youth—
hence the well-known clinical entity of inferior temporal dialysis of the young.
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About 75% of retinal breaks that occur after blunt ocular trauma are retinal dialyses.

The distribution of retinal breaks throughout the quadrants of the fundus is different for
each type of break.
Horseshoe tears are most common in the superior temporal quadrant; the second most
susceptible site is the superior nasal quadrant.
Operculated tears are also located most frequently in the superior quadrants, although
they tend to occur more posteriorly than horseshoe tears.
Atrophic retinal breaks are also usually located in the superior temporal quadrant, but
the second most common quadrant is the inferior temporal.
Dialyses are found most frequently in the inferior temporal quadrant

Natural history of untreated detachment
1. Usually, most untreated clinical rhegmatogenous detachments progress to near total or
total detachment and blindness.
2. Occasionally, a detachment remains indefinitely as a subtotal detachment with stable
borders and the creation of demarcation lines. This is most apt to occur in detachments
caused by inferior breaks, particularly small breaks or dialyses.
3. Rarely, subretinal fluid due to a superior retinal break settles inferiorly away from the
break, and the site of the original break flattens.
4. Very rarely, spontaneous reattachment occurs, usually associated with a very small
break and excellent presumed ―pumping‖ of the retinal pigment epithelium or closure of the
break by scar tissue.

30% of the retina lies anterior to the equator.

The pupil should be dilated to the maximum possible diameter. Mydriatics, such as 2.5% or
10% phenylephrine, used alone are totally inadequate; the moment the bright light is
projected into the eye, the strong stimulation to sphincter con- traction will overcome the
action of the dilator muscle, and the pupil will become miotic. On the other hand,
cycloplegics used alone, while much more satisfactory than mydriatics alone, do not give
maximum dilation but they do result in a dilation that is not affected by the strong light.
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In approximately 12% of symptomatic posterior vitreous detachments, however, a
careful search of the periphery reveals a tear of the retina.
If the flashes are associated with floaters, it is wise to assume that a retinal tear exists, until
proved otherwise.

Laser test:
Laser intensity is adjusted to create a medium-intensity laser spot in normal retina. This
same intensity is then applied to the area of the retina in question. Where retinoschisis is
present, a white spot will result, but where retinal detachment is present, there will be no
visible reaction to the laser.

Photomydriasis: Laser application in at least eight meridia is sometimes sufficient to
achieve adequate dilation. Laser spots are placed midway between the pupillary margin and
the iris root, causing contraction of the dilator muscle. If pupillary fibrosis is present, it may
be amenable to Nd: YAG laser transection.

If the choroidal detachment is not in the area of the retinal break, the surgeon should
simply proceed with retinal surgery. If, however, the choroidal detachment is in the area of
the retinal break or in the area where subretinal fluid must be drained, the surgeon should
begin the operation with drainage of the suprachoroidal fluid. Normal intraocular pressure
can be maintained during drainage with use of a pars plana cannula for the continuous
infusion of a balanced salt solution into the vitreous cavity. The surgeon may then proceed
immediately with conventional retinal reattachment surgery.

The ora serrata is the anterior limit of the sensory retina. It is characterized nasally by
prominent ora teeth, which point anteriorly. Between each pair of teeth is an ora bay. There
are approximately 48 ora teeth per eye. The pattern of serration is not present temporally,
where the ora teeth are small or absent

Detachment of the pars plana is more common on the nasal side, apparently because of the
narrower retinochoroidal adhesion. Detachment of the pars plana epithelium is an important
feature, and the pars plana must be carefully examined with scleral indentation to detect the
presence of breaks in the area, particularly along the anterior limit of the vitreous base.
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
It is helpful to recall that the distance from the ora to the equator is approximately 4 disc
diameters and that the equator is just slightly anterior to the vortex ampullae.

Drusen are more common in the equator than in the macula. Equatorial drusen may be
associated with reticular pigmentary degeneration and are most often found in the elderly.

Existence of narrow funnel shape is evidenced by indirect opthalmoscopy when anterior
end of funnel can be seen within 45° field of 20D condensing lens.

Lesions that might be confused with retinal detachment include degenerative
retinoschisis, choroidal detachment, tumors of the choroid, vitreous membranes, and whitewith-pressure or white-without-pressure.

A diagnostic feature of retinoschisis is the ―white Swiss cheese‖ appearance of the outer
layer of the schistic retina as it is frozen. In contrast, the retinal pigment epithelium deep to
an overlying detached retina appears dull orange when viewed during cryopexy.
Type 1 schisis detachment refers to detachment that does not extend beyond the area of
retinoschisis, whereas type 2 schisis detachment extends beyond the schisis. Type 2
schisis detachments generally require retinal detachment repair, whereas type 1 generally
do not.

Asymptomatic eyes include those with and without additional risk features. Cases in which
lesions are diagnosed in a second (―fellow‖) eye following a detachment in the first eye are
discussed in a separate section below.
The term ―non-fellow eye‖ indicates absence of a history of retinal detachment in the other
eye.

three basic steps in closing retinal breaks and reattaching the retina:
1. Conducting thorough preoperative and intraoperative examinations with the goal of
locating all retinal breaks and assessing any vitreous traction on the retina.
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2. Creating a controlled injury to the retinal pigment epithelium and retina to produce a
chorioretinal adhesion surrounding all retinal breaks so that intravitreal fluid can no longer
reach the subretinal space.
3. Employing an appropriate technique, such as scleral buckling and/or intrav- itreal gas, to
approximate the retinal breaks to the underlying treated retinal pigment epithelium.

Factors considered in the selection of a drainage site include (1) the distribution of
subretinal fluid when the eye is in a position at which drainage will be performed, (2) the
location and size of the retinal break(s), (3) the location and configuration of the buckle, (4)
the vascularity of the choroid, (5) features of vitreoretinal and epiretinal membrane traction,
and (6) the ease of exposure of the proposed drainage site.
The optimal locations for drainage are usually just above or below the lateral rectus muscle,
because major choroidal vessels are avoided and exposure of sclera is excellent.

Uveitis is rare in Still's disease, which is more common in boys.

The reduction in visual acuity caused by epiretinal membrane is related to distortion
produced in the outer retinal layers and does not depend on the size or degree of
transluscency of the membrane.

A positive Watzke Allen sign is seen in 95% of eyes with full thickness macular hole.

All patients of Macular Hole will report a positive laser beam (50—microns) sign.

Congenital cyst of retina: bilateral, same location, may look like RD, DD is melanoma.

Vascularization of the nasal retina is complete by (approximately) the eighth gestational
month. The temporal retina is completely vascularized 1 to 2 months later.
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
The risk of retinopathy of prematurity (ROP) does not correlate with the postdelivery age but
with gestational age (postconception age).

ROP is not DIRECTLY related with arteriolar oxygen level and not related to NEC.

Zone 1 is a circle of radius (not diameter ..!!) 30 degrees (twice the distance from optic
disc to macula) centered on the optic disc. Zone 2 extends to the nasal ora and the temporal
equator (radius 60 degrees). Zone 3 is the remaining crescent-shaped region anterior to
zone 2 in the temporal retina.

In ROP, Pseudostrabismus results from a change in angle kappa caused by macular
ectopia from peripheral cicatrization. Pseudoexotropia is more common than
pseudoesotropia.

Benson‘s disease is Asteroid hyalosis.

65% of premature infants with birth weight <1,250 g will develop some stage of ROP.

Guiat‘s sign: Tortuosity of retinal veins in arteriosclerosis

In acute leukemic oculopathy, Flame-shaped nerve fiber hemorrhages are the one
most common funduscopic finding. White-centered hemorrhages (Roth's spots), cotton-wool
spots, optic disc swelling, and perivascular infiltration also may be seen but are less
common.

Diffuse arteriolar attenuation is not a characteristic finding in renal failure, although it may
occur if there is severe associated hypertension.

In albinism, fewer ganglion cell fibers decussate at the chiasm than in normal visual
pathways.
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juvenile retinoschisis from Goldmann-Favre dystrophy:
The electrooculography (EOG) is abnormal in Goldmann-Favre disease and normal in Xlinked juvenile retinoschisis.
Goldmann-Favre disease is autosomal recessive.
Both diseases have abnormal electroretinograms (ERGs). In mild forms of juvenile
retinoschisis, the scotopic b-wave is lost, with preservation of the a-wave. In severe cases,
the ERG is extinguished, as it is in most cases of Goldmann-Favre.
Both diseases are characterized by foveal and peripheral retinoschisis, as well as retinal
pigment epithelial disturbances, although the latter are more severe in Goldmann-Favre.

Cone dystrophy (not Stargardt‘s..!!) is the most common ―bull's-eye‖ maculopathy.

Retinitis punctata albescens is not a form of congenital stationary night blindness (CSNB)
but is progressive (although more slowly than typical retinitis pigmentosa).

Visual function in the pattern dystrophies of the retinal pigment epithelium (RPE) is
usually good.

Aicardi's syndrome is limited to the female sex because it is X-linked dominant. It is lethal
in male infants or fetuses.

In CSR, The early FFA finding is the presence of smoke stack or ink blot and the late
FFA finding is the presence of mushroom or umbrella shape accumulation of dye

Think of Diabetic Retinopathy in a case of recurrent stye with peripheral neuropathy.

In pneumatic retinopexy, Grade C PVR is a contraindication as the retina is usually rigid in
these cases. The success rate is higher in Phakic than pseudophakic patients.
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Risk factors for expulsive suprachoroidal hemorrhage include increased axial length,
glaucoma, atherosclerosis and previous expulsive suprachoroidal haemorrhage. It may be
reduced by
o
Small incision surgery
o
Control of IOP
o
Control of HTN

It is polycythemia and not thrombocytopenia which may be associated with VHL. It is due
to erythropoietin secretion from cerebellar hemangioblastoma.

Early CMV retinitis and CWS can be differentiated by presence of hemorrhage and
enlargement of the lesion in case of former.

ROP like condition but without history of prematurity: FEVR (it is AD condition)

ERG:
o
Reduction in b wave: diffuse degeneration or dysfunction of cells in the inner
nuclear layer (Muller or bipolar cells)  siderosis, CRVO, vigabatrin
o
Reduction in both a and b wave: Cancer associated retinopathy CAR

Becker's phenomenon: Pulsation of the retinal arteries in Basedow's disease (Grave’s
disease)

Coats'-type retinal vascular changes have been noted in patients with
facioscapulohumeral muscular dystrophy, Turner's syndrome, Senior-Loken syndrome, and
one variant of the epidermal nevus syndrome. In addition, Coats'-like retinopathy has been
noted in up to 3.6% of patients with retinitis pigmentosa.
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
Salmon in Sickle cell patients: actually they have Smoked salmon. Salmon patch
haemorrhages (and therefore red as in smoked salmon cf. with poached salmon which is
pink) occur from pre-retinal and internal lining membrane haemorrhages occurring near an
occluded arteriole.

Asteroid Hyalosis is distinguished from vitreous haemorrhage on ultrasound by

o
The asteroid hyalosis opacities are dense and uniformly high reflective
o
They are separated from the retina by an echolucent space.
Macropsia (due to crowding of photoreceptors): ARMD, Macular scar
Micropsia (due to separation of photoreceptors): Macular oedema, CSR, Chorioretinitis


Gregg's syndrome: Congenital Rubella Embryopathy
o
Congenital cataracts, deafness, cardiac defects (patent ductus)
o
Retention of lens nuclei in embryonic nucleus (not pathognomonic)
o
Virus remains viable in lens for several years
o
"Salt and pepper" retinopathy
o
May have congenital glaucoma, inflammation
PRN: Pro Re Nata = Treat and Observe
o
Regular follow up
o
Treat if signs of exudation
TAE: Treat And Extend

o
Treat at every visit
o
Gradually extend treatment interval
Photosensitisers for PDT:
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1st generation

Photofrin (porfimer sodium)

transient-induced photosensitivity of the skin for 6 to 8 weeks after injection

less than optimum activation wavelength (630 nm) for maximizing tissue
penetration

relatively low extinction coefficient
2nd generation


benzoporphyrin derivative (BPD):

absorption maximum at about 690 nm

formulated in liposomes as its hydrophobic
Purlytin

Hydrophobic

chlorin-type photosensitizer that has shown minimal cutaneous
toxicity

Dilated NON TORTUOUS retinal veins:  always think for Ocular Ischemic Syndrome.

Diabetes is not an independent risk factor for BRVO.

AREDS is the only study in medicine showing benefit of dietary supplements ??

Electrodes for ERG:
o
Hard contact lens electrodes
o
DTL- Dawson Trick Litzkow fiber electrode
o
anomalous polyvinyl alcohol gel electrode
o
Dermal electrodes
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Electronegative B wave in ERG:
o
CSNB
o
XL retinoschisis
o
CRAO
o
MAR
Antibody against alpha-enolase
o
Autoimmune retinopathy
o
CAR
o
Wet ARMD
o
Behcet‘s disease

ESCS: AR, NR2E3, loss of transcription inhibitor by photoreceptor cell

Anecortave acetate, marketed as Retaane 15 mg for the treatment of AMD, is a synthetic
analog of cortisol with angiostatic but not glucocorticoid receptor mediated activity.
Anecortave acetate is delivered as a posterior juxtoscleral depot (PJD) onto bare sclera
near the macula. Anecortave acetate is administered outside the globe with a curved, blunttipped cannula. The cannula is inserted between Tenon‘s capsule and the sclera and the
drug forms a depot directly behind the macula where it is slowly released over 6 months. A
counter-pressure device (CPD) is used to prevent reflux of the suspension.

Copper was added to the AREDS formulations containing zinc to prevent copper deficiency
anemia, a condition associated with high levels of zinc intake.

Multiple sub-ILM hemorrhges: shaken baby syndrome (abusive head trauma)
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
OPL is the watershed zone for retinal circulation.

Verhoff‘s membrane = COST, Cone Outer Segment Tips

Absolute risk of RD in lattice degeneration is 1% over 10 years.

Mineralocorticoid receptor is involved in rat and human ocular chorioretinopathy. (journal
of clinical investigations, 2012, 122/7)  trial of EPLERENONE 25 mg OD for 1 week and
50 mg OD for 3 weeks.

o
Specific mineralocorticoid receptor antagonist
o
Used for HTN, CHF, aldosterone secreting adenoma
o
CSCR may be related to mineralocorticoid receptor (MR) activation (glucocorticoid
bind to MR)
Seven rings of blunt trauma to eye
1. Central iris: Sphincter tear
2. Peripheral iris: Iridodialysis
3. Anterior ciliary body: Angle recession
4. Separation of ciliary body from the scleral spur: Cyclodialysis
5. Trabecular meshwork: Trabecular meshwork tear
6. Zonules/lens: Zonular tears with possible lens subluxation
7. Separation of the retina from the ora serrata: Retinal dialysis

A positive scotoma, in which patients complain of something obstructing their central
vision, is a symptom of macular disease. This is in contrast to optic neuropathy which
typically causes a missing area in the visual field (a negative scotoma).
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
Despite its close association with the choroid, the RPE is considered a part of the retina
because it is from the same embryologic germ cell layer—neural ectoderm.

Glutamate is the excitatory neurotransmitter released by photoreceptors, bipolars, and
ganglion cells.
Glycine and GABA are inhibitory neurotransmitters released from amacrines; it is unclear
what neurotransmitter horizontal cells secrete (?GABA)

Cleft palate can be associated with stickler syndrome.

Nonsyndromic congenital retinal nonattachment (NCRNA) comprises congenital
insensitivity to light, massive retrolental mass, shallow anterior chamber, microphthalmia,
and nystagmus.

In choroideremia, in contrast to primary retinal dystrophies, the fovea is spared until late.

The internal elastic lamina separates the intima from the media. Retinal arterioles contain
smooth muscle within their walls, but unlike arteries the internal elastic lamina is
discontinuous.

Dynamic traction: pathogenesis of retinal tears and rhegmatogenous RD.
Static traction: pathogenesis of tractional RD and proliferative vitreoretinopathy. 3 types 
tangential, anteroposterior and bridging (trampoline)

Pan Retinal 2.2 is a hybrid lens which uniquely combines magnification nearly that of the
20D lens with a field of view approaching that of the 30D lens. Excellent for virtually every
examination procedure, including small pupil examinations.

Myopia: recent evidences
o
Outdoor activity is protective
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
Vitamin D (regulation of eye growth via retinoic acid receptors)

Less divergent light

Ambient light levels

Less peripheral defocus light
Peripheral retinal defocus

Myodesopsia: perception of eye floater is known as myodesopsia.

CAR: deceased rod-cone amplitude in ERG
MAR: selective loss of scotopic B wave (similar finding seen in CSNB)

the indirect ophthalmoscope can be used to see the „forest‟ and the slit lamp to see
the individual „trees‟.

The retina itself is a thin transparent tissue, which is thickest near the optic nerve, where it
measures 0.56 mm. It thins to 0.18 mm at the equator and to 0.1 mm at the ora serrata. At
the foveal area, it has thinned to about 0.2 mm. The nerve fiber layer increases at the edge
of the disc and is the only retinal structure that continues into the disc to become the optic
nerve.

Issues in naming cones:
Two schemes have been used: RGB (red, green, blue) and LMS (long-, mid-, and shortwave)
The LMS system denotes a cone's relative spectral peak to avoid confusion between
perceptual names (red, green, blue) and VP absorption peaks (yellow-green, green, violet)

The primate retina possesses three image-forming photoreceptor chromatypes.
Rods express the RH1 opsin group VP 499, have a unique rod structural phenotype, and
selectively contact rod BCs and HC axon terminals.
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Blue cones express the SWS1 opsin group VP 420, have a subtle but unique blue cone
morphology, contact cone BCs and HCs, with a strong preference for a blue ON BC.
Red and green cones express VP 530 or VP 560 from the LWS opsin group, are
structurally indistinguishable from each other, contact cone BCs and HCs, but avoid the blue
ON BC.

The resolution limit set by the packing density of the cones is similar to, but slightly higher
than, the limit set by the optics of the eye. As a result, under ideal conditions, an observer
with excellent vision can just resolve fine detail whose angular subtense approaches
that of a single cone.
The exact shape of the fall in acuity with eccentricity depends on the type of target used, but
acuity falls roughly to half at 1° and to one-fourth at 5°.

Cone dystrophy implies a panretinal disorder and not a localized dysfunction, such as in
macular degeneration, where the photopic ERG is normal. Cone dystrophies are
characterized by a decreased or nonrecordable photopic ERG and a normal scotopic ERG.

Normal human color vision is trichromatic, mediated by three well-separated classes of
cone photoreceptor commonly referred to as the blue, green, and red cones. Calling them
short-, middle-, and long-wavelength sensitive, abbreviated S, M, and L cones minimizes
confusion that can arise from giving them color names.
Photopigment molecules within each cone are responsible for the spectral properties of the
cones. Each photopigment molecule is composed of two parts; a protein termed the opsin,
and an 11-cis-retinal chromophore.
The official names for the genes encoding the L, M, and S cone opsins are OPN1LW, OPN1
MW, and OPN1SW respectively. Both OPN1LW and OPN1 MW are on the X-chromosome
at position Xq28, OPN1SW is located on chromosome 7 at 7q32.1. The location of
OPN1LW and OPN1 MW on the X-chromosome accounts for the great gender difference in
the prevalence of color vision deficiencies.

The suffix -opia denotes dichromacy. The suffix -anomaly denotes anomalous
trichromacy in which two of the cone classes are more similar in spectral sensitivity than
the corresponding normal cones:
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
In ∼25% of humans a cilioretinal artery hooks around the temporal margin of the optic disk
and provides a portion of the macula with the arteriolar supply.

Retinal circulation: Low level of flow (15 – 34 mg/min), High O2 extraction (40%)
Choroidal circulation: High level of flow (677 – 735 mg/min), Low O2 extraction (4%)


Kimmelstiel-Wilson (K.W.) syndrome: These patients had hypertension, generalised
edema and renal involvement as indicated by the presence of protein, casts and R.B.Cs in
their urine with or without pyuria. Majority had raised blood urea.
Common Ocular Fluorophores
o
Lipofuscin in the retinal pigment epithelium (RPE) (A2E)
o
Extracellular vitelliform material
o
Crystalline lens
o
Optic nerve head drusen
o
Astrocytic hamartoma
o
Sclera

Coats disease may be part of a spectrum of related genetic disorders known as retinal
hypovasculopathies which includes Norrie disease, familial exudative vitreoretinopathy
(FEVR), fascioscapulohumeral muscular dystrophy (FSHD), and the osteoporosis
pseudoglioma syndrome

melanocytoma appears to have an equal incidence in all races, whereas uveal melanoma is
uncommon in black people

Ablatio fugax: photocoagulation and cryotherapy of peripheral tumors in VHL can often
lead to massive retinal hard exudate accumulation and retinal edema in the macula,
contributing to further decrease in vision following treatment.
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2RT: Nonthermal Retina Regeneration Therapy (2RT; Elex, Adelaide, Australia)
o short-pulsed laser treatment (pioneered by John Marshall and Peter Hamilton of
UK)
o to treat diabetic maculopathy and macular edema at an earlier stage
o Q-switched, green Nd:YAG laser with a wavelength of 532 nm
o pulse duration is 3 nanoseconds with energy of 1 J per pulse which causes the RPE
cells to release matrix metalloproteinase enzymes, which are believed to 'clean up'
the bruch's membrane. The laser thus triggers what is described as
photoregeneration of the retinal pigment epithelium and Bruch's membrane.

Low Fluence PDT:
o
PDT by itself also causes upregulation of VEGF and induces fibrosis
o
Low fluence photodynamic therapy is done using
o

light intensity of 50mJ/m2

300mW of power

83 seconds

compared to standard fluence where 100 mJ/m2 at 600mW of power for 83
seconds.
For CNVM, CSR etc

Pseudoxanthoma elasticum and myopia may cause spontaneous defects in bruch‘s
membrane, making the patient prone to development of choroidal neovascularization.

Diffuse pigmentary retinal changes in congenital rubella syndrome may be confused with
retinitis pigmentosa. However, the ERG is normal in congenital rubella.
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
The pattern electroretinogram (PERG) measures the electrical response to an alternating
pattern stimulus that has a constant overall retinal luminance, and the response appears to
be localized to retinal ganglion cells.

abnormal ERG and a normal EOG:
o
congenital stationary nightblindness
o
X-linked retinoschisis
o
cone dysfunction

The choriocapillaris does not communicate freely with the optic disc capillaries. The
choroidal circulation is from the posterior ciliary arteries; the optic disc and retinal arterioles
are branches of the ophthalmic artery.

choroidal hemangioma

o
This is an uncommon hamartoma that has been reported to exhibit two clinical
growth patterns:
o
1) circumscribed tumors without systemic disease, and
o
2) diffuse tumors often associated with the Sturge-Weber syndrome.
o
The lesion is histologically benign; however, the lesion can lead to an exudative
retinal detachment if untreated.
o
Therapeutic options are photocoagulation and cryotherapy.
o
The solitary type is histologically characterized by a cavernous hemangioma with
sharply demarcated pushing borders, often compressing surrounding melanocytes
and choroidal lamellae. This is visible clinically as a ring of hyperpigmentation in the
periphery of the lesion and on fluorescein angiography as a ring of blockage of the
underlying choroidal fluorescence.
o
von Hippel-Lindau disease has vascular lesions of the retina and cerebellum;
however, these are capillary hemangioblastomas.
Retinal Dialysis and Detachment
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o
Approximately 10% of dialysis-related detachments present immediately
o
30% within 1 month
o
50% within 8 months
o
80% within 2 years
Shifting Fluid:
o
Exudative RD
o
Old RD
o
Aphakic RD
Lattice Degeneration:
o
10% of the population and is bilateral in 30-50% of affected patients
o
Crisscrossing, fine, white lines that account for the name lattice degeneration are
present in roughly only 10% of lesions and most likely represent hyalinized blood
vessels
o
Various pigmentary disturbances occur in more than 80% of lattice lesions. Whiteyellow flecks, similar to that seen with degenerative retinoschisis, are an additional
common associated feature.
o
Atrophic retinal holes and tractional retinal tears may complicate lattice degeneration
and increase the risk of retinal detachment.
o
When retinal thinning and pigmentary disturbances are found along retinal vessels,
these lattice lesions are referred to as radial perivascular chorioretinal degeneration
and are classic findings in Wagner and Stickler disease, a familial vitreoretinal
degenerative syndrome
o
Retinal detachment is a relatively rare complication of lattice degeneration (<1% of
patients with lattice degeneration) but is associated with as many as 40% of all
rhegmatogenous retinal detachments.
o
Retinal detachments caused by lattice degeneration occur most commonly by a
tractional tear at the cuff or posterior margin of the lattice lesion, or less commonly by
means of an atrophic hole within the zone of lattice.
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Dhaval Patel MD
o
Tractional tears located at the margin of lattice account for 55-70% of retinal
detachments in lattice degeneration and are the result of a posterior vitreous
detachment.
o
Atrophic holes account for 30-45% of retinal detachments in lattice
degeneration.
3 invariable features: thinning or atrophy of the inner retinal layers, vitreous
liquefaction overlying the area of thinned retina, and vitreous condensation and
exaggerated vitreoretinal attachments at the borders of the lesions.
Different RDs:
o
Subclinical RD: subclinical retinal detachment (SCRD), which is defined as a retinal
break with surrounding subretinal fluid extending at least 1 disc diameter (DD) away
from the break, but no more than 2 DD posterior to the equator.
o
If there is less than 1 DD of fluid, then it is a break without detachment.
o
Subtotal RD: atleast one quadrant is attached.
o
Total RD: complete detachment of Retina
Iridofundal Coloboma
o
Incidence-0.14%,2\3 B\L, 40% develop retinal detachment (0.6-1.7% of all RD)
o
60% are bilateral
o
Aymptomatic
o
Diminished vision - coloboma involving macula or assoc. with Nystagmus/RD
o
Leucocoria
o
Scotoma corresponding to area of coloboma
o
Appears as vertically oval ,glistening white defect of varying size can be
associated with microphthalmos, cataract and myopia.
o
In the normal eye, optic fissure closes 33 to 40 days after conception.
o
Failure of the embryonic fissure to close along the inferonasal aspect of the optic cup
and stalk
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Endophthalmitis
o
Endogenous Endophthalmitis: A 17-year prospective series and a review of 267
cases published in 2003 found that 67% of patients had an extraocular focus of
infection. Liver abscess was the most common extraocular focus for endogenous
bacterial endophthalmitis, followed by endocarditis.
o
Diabetes mellitus (DM) is a risk factor for both types of endophthalmitis. Both
types of endophthalmitis are associated with pain and decreased long-term visual
acuity. Vitrectomy and/or vitreous tap with intravitreal antibiotics can be used to treat
both forms of endophthalmitis. In endogenous endophthalmitis, Streptococcus and
Staphylococcus aureus predominate. Intravenous antibiotics may be indicated for
endogenous endophthalmitis to treat the source, whereas they usually play no role in
the management of postoperative endophthalmitis (especially postoperatively in
patients who have undergone cataract surgery, as per the Endophthalmitis
Vitrectomy Study [EVS] study).
o
Saccular Endophthalmitis: Delayed-onset endophthalmitis following cataract
surgery develops when an organism of low virulence becomes trapped within the
capsular bag. The infection is caused most frequently by P. acnes and occasionally
S. epidermidis, Corynebacterium spp. or Candida parapsilosis.
o
Cluster endophthalmitis is a term defined as the occurrence of two or more than
two infections at a time, or the occurrence of repeated post- operative infections
under similar circumstances, i.e with the one surgeon, same staff, same operation
theatre, same equipments, etc. These infections usually occur as a result of a breach
in standard protocol of pre-operative, intraoperative and postoperative care. Cluster
post-operative endophthalmitis is generally exogenous in origin.
o
Filtering bleb—associated Endophthalmitis: The most common organisms
responsible for this condition include Streptococcus species (Gram-positive cocci in
pairs or chains) and Haemophilus influenzae (Gram-negative coccobacilli). Other
organisms, such as Staphylococcus epidermidis (Gram-positive cocci in clusters)
and Gram-negative species, have been implicated less frequently. Fungal causes
are rarely associated with filtering bleb—associated endophthalmitis.
o
Delayed-onset endophthalmitis after cataract surgery include Staphylococcus
epidermidis, fungal species such as Candida, and Propionibacterium acnes.
Endophthalmitis caused by P. acnes typically presents from 3 months to 2 years
after surgery, whereas S. epidermidis generally presents within 6 weeks and
Candida within 3 months. The presence of a white plaque within the capsular bag
specifically suggests the diagnosis of P. acnes.
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
Schwartz's syndrome is high IOP associated with a rhegmatogenous retinal detachment.
Photoreceptor outer segments migrate transvitreally into the aqueous, block the trabecular
outflow pathways, and result in IOP elevation.

SCHLEIRENING: drainage of SRF through breaks of retina in RD cases during PFCL
assisted surgery

GLUT-1 is the most common transporter of glucose in retina.

With 1 ml of gas bubble, IOP by schiotz tonometry shows error of 8 mmHg in range of 10-20
mmHg and 15 mmHg in range of 30-40 mmHg.

In macular translocation, retina is rotated around optic nerve by 35-50o.

Ocular ischemic syndrome
o
dot and blot hemorrhages in the midperipheral retina that may extend into the
posterior pole
o
Ocular perfusion pressure on ophthalmodynamometry is reduced substantially with
collapse of the central retinal artery with minimal pressure.
o
Anterior segment manifestations include a limbal flush, anterior chamber cell and
flare, neovascularization of the iris and angle, and cataract.
o
Hypotony from decreased aqueous production or elevated IOP from
neovascularization of the angle may be present.
o
High-grade carotid stenosis is the usual cause.
o
Many of these patients also have systemic hypertension, atherosclerosis, and
diabetes mellitus.
o
The prognosis of this condition is usually poor, especially if neovascularization is
present.
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
The natural course of Leber's stellate neuroretinitis is spontaneous resolution over
several months. The prognosis is excellent, and over 80% of patients have visual acuity
better than 20/40.

Floaterectomies:


o
FFQ 22 test: Well-Being-Index of WHO (5 questions) together with 17 questions of
the Frankfurt Floater Questionnaire
o
National Eye Institute Visual Function Questionnaire-25 test (NEI-VFQ-25)
o
1-step single-incision-site core vitrectomy (Intrectomy) procedure
Approaches for to anti-VEGF treatment
o
―treat-and-extend‖ protocol: the patients are treated during each visit regardless of
activity. If there is no sign of activity, the control and treatment intervals are extended
gradually, whereas if there are signs of recurrence, the intervals are shortened.
o
As needed treatment (PRN- Pro Re Nata): where patients are seen monthly and
treated if signs of exudation appear.
Adaptive Optics Scanning Laser Ophthalmoscopy (AO-SLO)
o
For AMD
o
Liquid crystal on silicone spatial light modulator
o
Measure and correct subject‘s aberration
o
Photoreceptor analysis: 0.34 x 0.34 mm, 32 frames per second
o
Blood flow analysis: 0.82 x 0.41 mm, 64 frames per second

EOG shows reduced Arden ratio in autosomal dominant CME

Vitreomacular interface (VMI) diseases
o
Full thickness macular hole (FTMH)
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o
Lamellar macular hole (LMH)
o
Epiretinal membrane (ERM)
o
Vitreomacular traction (VMT)
Dhaval Patel MD
International Vitreomacular Traction Study (IVTS) Group Classification System
o
In 2012
o
designed to reflect new insights derived from SD-OCT and, as such, is strictly
anatomy-based (derived from OCT images alone).

Vitreomacular Adhesion: perifoveal vitreous separation with continuing
vitreomacular attachment within a 3-mm radius of the foveal center, and
completely normal retinal anatomic morphology.

Vitreomacular Traction: same as VMA but with abnormal retinal anatomic
morphology

Full Thickness Macular Hole: foveal lesion with interruption of all retinal
layers from the ILM to the RPE

Fingolimod-associated macular edema (FAME) generally occurs within 4 months of
initiating therapy and affects 0.5% of users. It appears to be dose-dependent (observed in
only 2 patients taking the FDA-approved 0.5-mg dose) and typically resolves upon cessation
of therapy.

OCT is VEGF-meter of retina. It identifies 3 basic types of fluid collection in the retina.

o
Intra-retinal fluid
o
Sub-retinal fluid
o
Sub-RPE fluid
Two types of reactions can be caused by photosensitizer:
o
type I reaction: it can react directly with substrates to form radicals or radical ions
o
type II reaction: it can react with endogenous ground state oxygen (3O2) by means
of an energy transfer mechanism in producing excited oxygen species, such as
singlet oxygen (1O2). This latter reaction is known as the photodynamic reaction.
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
The risk for retinal detachment is 4-fold greater after pseudophakic cataract surgery than
in the patient's untreated eye, according to a large, population-based Danish study.

A reanalysis of data from AREDS has identified genetic polymorphisms that predict
which patients with moderate to severe age-related macular degeneration (AMD) are most
likely to respond to antioxidant or zinc supplementation.
In a related calculation, the researchers estimate that "genotype-directed therapy of the
study population would have more than doubled (>200%) the reduction in AMD
progression rate compared with treatment with the AREDS formulation."

The Atherosclerosis Risk in Communities (ARIC) study found that patients with moderate to
severe retinopathy had 2.37 times the risk for stroke compared with those with no
retinopathy. Patients with mild retinopathy had 1.35 times the risk.

The Post-Injection Endophthalmitis Study Team conducted a retrospective case-control
study of endophthalmitis cases. Topical antibiotic use was associated with a greater than
50% increased risk for endophthalmitis and culture-positive endophthalmitis.

Argus II Retinal Prosthesis System
o
Mark Humayun, MD
o
designed by Second Sight
o
epi-retinal
o
patients with severe to profound outer retinal degeneration, whose remaining visual
acuity is worse than 2.3 logMAR in both eyes
o
best visual acuity attained was 20/1260 (1.8 logMAR)
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Uvea

Review of Uveitis Therapy

Local Therapies
o
o



FDA approval for ―endogenous anterior uveitis‖: 6/12

Efficacy compared with prednisolone acetate

Potential side effects: IOP, cataract; use in pediatrics
Ozurdex and Retisert

FDA approved for intermediate and panuveitis

Multicenter Uveitis Steroid Treatment (MUST) trial results for Retisert
o
Intravitreal methotrexate for uveitis: Efficacy for cystoid macular edema
o
Intravitreal TNF inhibitors: Caution re: intravitreal infliximab
Emerging Local Treatment: Sirolimus
o
Periocular administration preliminary trial
o
Intravitreal trial: Sirolimus as Therapeutic Approach to Uveitis (SAVE) trial
New Systemic Agent Using Classical Immunomodulatory Pathways: Voclosporine
o

Status of difluprednate
LX211 LUMINATE trial → Uveitis development Withdrawn
Biologics
o
o
Tumor necrosis factor inhibitors

Relative efficacy of infliximab, adalimumab, and etanercept for uveitis

Golimumab, certolizumab
Anti-CD20

Rituximab
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
Use in granulomatosis with polyangiitis

Use in uveitis/scleritis
o
Anti-IL17: AIN457 clinical trial
o
IL-1 inhibitors: Gevokizumab, anakira, canakinumab, rilocept
o
IL-6 inhibitors: Toclizumab

Scleritis is not a feature of Behçet's disease.

Diffusely distributed keratic precipitates over the corneal endothelium:
o
Fuchs' heterochromic iridocyclitis
o
Sarcoidosis
o
Syphilis
o
kerato uveitis
o
toxoplasmosis

In ocular histoplasmosis, there is no vitreous inflammation.

IRIS ROSEOLA: dilated iris capillaries
o

Dhaval Patel MD
Occurs in granulomatous iridocyclitis especially syphilis like
WSS with Female predominance  MAMA
o
MEWDS
o
AZOOR
o
MFC
o
AIBSE
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
Dhaval Patel MD
ddx of uveitic glaucoma
HSV, HZV, posner-schlossman syndrome, fuchs' heterochromic iridocyclitis, sarcoidosis,
rarely toxo, syphilis, S.O.

DD of Hypopyon uveitis: HLA-B27 associated (most common), infection, FB, Behcet's,
VKH, malignancy (leukemia, Rb), toxic (RIFABUTIN)

HLA-B27-associated DZs: PAIR
o
Ankylosing Spondylitis
o
Reactive arthritis (Reiter's)
o
Psoriatic arthritis
o
IBD

Blau syndrome: familial granulomatous arthritis, AD, granulomatous uveitis, dermatitis,
arthritis, defect in NOD2/DARD15 gene, autoinflammatory dz, may respond to anakinra (IL1RA)

drug-related uveitis: rifabutin and cidofovir, bisphosphonates, Bactrim, topical
prostaglandins

eye drop which causes drug-induced uveitis: metipranolol

sugiura's sign: perilimbal vitiligo seen in VKH

primary intraocular lymphoma (PIOL): IL10>IL6
(10>6  which should not confuse you now)

ibopamine: increases aqueous production (Italy)
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
drug which may worsen MS: infliximab

drug-induced lupus caused by: infliximab

Jenson‘s Juxtapapillary Choroiditis: histoplasmosis should be considered, differentiate it
from papilledema.

'Cracked mud appearance' of Progressive outer retinal necrosis (PORN), choroideremia??

Uveitis and poliosis:
1. sympathetic ophthalmia
2. VKH

Arlt‘s triangle: (Ehrlich–Türck line) base-down triangle of central keratic precipitates in
uveitis

Kunkmann–Wolffian bodies: Small white peripheral iris spots that resemble Brushfield
spots but occur in normal individuals. They are more peripheral than brushfield‘s apots
which are around midperiphery.

Kyreileis‘ plaques: White–yellow vascular plaques in toxoplasmosis

Lander‘s sign: Inferior preretinal nodules in sarcoidosis

Patient with uveitis undergoing cataract surgery, Prophylactic systemic steroid treatment is
only recommended in patients with previous macular oedema caused by the uveitis.
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
JIA is not the same as juvenile rheumatoid arthritis (JRA); the former is negative for
rheumatoid factor whereas the latter is positive. JRA is the same disease as rheumatoid
arthritis except that it occurs before the age of 16 years.

In Fuchs‘ heterochromic iridocyclitis, the fine ‗‗stellate‘‘ KP are found scattered diffusely
on the entire posterior surface of the cornea, unlike most KP, which are located in the
inferior cornea.

In Uveitis, Low intraocular pressure (IOP) may occur as a result of reduced secretion of
aqueous by the ciliary epithelium. Occasionally the intraocular pressure may be elevated
(hypertensive uveitis) as in herpetic uveitis and Posner–Schlossman syndrome.

In CAU, Aqueous flare may be more marked than cells in eyes with prolonged activity and
its severity may act as an indicator of disease activity (contrary to previous teaching).
The classical teaching that only cellular reaction in the anterior chamber represents active
inflammation has been challenged. Flare is caused by chronic break-down of the blood–
aqueous barrier, but the intensity of the flare can also indicate an active process, which
may respond to therapy.

Iris atrophy that is sectoral occurs characteristically in herpes simplex and herpes
zoster. Diffuse iris atrophy occurs in Fuchs uveitis syndrome.

Large KPs in granulomatous disease have a greasy (‗mutton-fat‘) appearance. They are
often more numerous inferiorly and may form in a triangular pattern with the apex pointing
up = Arlt triangle

DUSN is thought to be caused by migration of a nematode under the retina.

Onchocerciasis: Also known as river blindness, this is caused by infection with the filaria
parasite Onchocerca volvulus, which is transmitted by the bite of species of Simulium flies
(so-called buffalo gnats). Clinically there are skin changes, nodules and eye changes that
can lead to blindness. The nodules develop in subcutaneous tissue especially near bony
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structures and contain living or dead adult worms. Fundus of oncocerciasis is known as
Ridley‘s fundus.

MAGIC Syndrome: Mouth and genital ulcers with inflamed cartilage syndrome is a
cutaneous condition with features of both Behçet's disease and relapsing polychondritis

Dadizumab (Zenapax): A completely humanised IL- 2 receptor antibody used in kidneytransplant recipients, has shown encouraging clinical results in uveitis patients. In a phase 2
trial, subcutaneous daclizumab was injected at the dose of 2 mg/kg separated by 2 weeks
and then 1 mg/kg subcutaneous(SC) every 2 weeks for 26 weeks. The objective of the trial
was to reduce the load of the other immunosuppressive agents by half. Immunosuppressive
therapy was tapered off in a staggered fashion to SO% or less in 8 to 12 weeks. At 12
weeks, 10 of the lS patients (67%) receiving SC daclizumab successfully achieved the
primary end point of reducing concomitant immunosuppression load by SO%.

Anakinra: Anakinra is a recombinant, human, nonglycosylated IL-1 receptor antagonist
(IL-1RA). It inhibits IL-1 activity, downregulating the proinflammato1y functions of IL-1
including chemotaxis, activation of antigen-presenting cells, and the upregulation of cell
surface adhesion molecules involved in leucocyte trafficking. The use of Anakinra has so far
been reported in few cases of scleritis associated with rheumatoid arthritis and few cases of
posterior uveitis. It has been used in the dose of 100 mg/ day and the main side effects have
been the injection site reactions.

taches de bougie is a French of candle-wax drippings.

Phacoanaphylactic uveitis is an immune complex disease that develops when normal
tolerance to lens protein is lost, not a cell-mediated rejection of "foreign tissue" (Contrary
to prior teachings lens proteins are not totally sequestered or organ specific. They are
normally found in aqueous and expressed in other extraocular tissues. Anti-lens antibodies
are found in some normal individuals).

AC flare: Tyndal effect  focused beam of light illuminating the anterior chamber becomes
visible, just as a projector beam is visible in a smoky room. This phenomenon, which is
termed aqueous ―flare‖ or ―ray,‖ is caused by the Tyndall effect.
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
AC cells: The cells normally move with the convection currents in the aqueous. (They sink
anteriorly where the aqueous is cooled by the cornea and rise posteriorly where the
aqueous is heated by the iris.) Absence of cellular convection currents may indicate clotting
of fibrin-rich aqueous in a case with severe vascular permeability.

Blood level of cyclosporine: 100-150 ug/ml

Nozik technique: a 25-gauge, 1/2-inch needle is used. If the injection is given in the
superote m poral quadrant (the preferred location), the upper eyelid is retracted and t he
patient is instr u cted to look down and nasally. After anesthesia is applied with a cotton
swab soaked in propa racaine or tetracaine, the needle is placed bevel-down against the
sclera and advanced through the conjunctiva and Tenon capsule using a side-to- side
movement, which allows the physician to deter mine whether the needle has entered the
sclera or not. As long as the globe does not torq ue with the side-to-side movement of the
needle, the physician can be reasonably sure t hat the needle has not penet rated t he
sclera. Once the needle has been advanced to the hub, t he corticosteroid is injected into
the sub-Tenon space. Complications of the superotem poral approach include upper lid
ptosis, periorbital hemorrhage, and globe perforation.

The Goldmann-Witmer (GW) coefficient is a test that compares the levels of intraocular
antibody production to that of serum, as measured by enzyme-linked immunosorbent assay
(ELISA) or radioimmunoassay. The coefficient is defined as GW = X/Y; where GW =
Goldmann-Witmer coefficient; X = specific antibody in aqueous or vitreous divided by total
IgG in aqueous or vitreous; and Y = specific antibody in serum divided by total IgG in serum.
A GW ratio > 4 is diagnostic of local antibody production to a specific microbial pathogen.
It‘s especially useful for ARN.

7 g of protein/100 mL of blood, but only 11 mg of protein/100 mL of aqueous.

pink hypopyon: Serratia marcescens endophthalmitis. Cytologic examination reveales no
erythrocytes, and the pink color is due to the bacteria.

KPs
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o
o
Dhaval Patel MD
Types of KPs

Fine/coarse (lymphocytes and plasma cells) – found in allergic or acute
iridocyclitis.

Mutton fat (Macrophage and epitheloid cells) – found in granulomatous
uveitis – e.g. TB, sarcoidosis.
fresh KPs/Old KPs

Fresh KPs – Solid, round, white, fluffy

Old KPs – Faded, shrunken, pigmented, crenated edge

The absence of CME distinguishes Fuchs‘ heterochromatic iridocyclitis from other uveitis
syndrome with chronic vitritis.

Aspirin is the treatment of choice for patients with Kawasaki syndrome. Systemic
corticosteroid therapy use is associated with an increased rate of coronary artery aneurysm
formation and is therefore contraindicated.

Serpiginous choroidopathy (geographic helicoid peripapillary choroidopathy GHPC)
is a chronic, recurrent, indolent disease of unknown etiology. It usually affects adults with
painless loss of vision. Lesions are peripapillary or perimacular and, in the active phase,
have inflammation along the edges. Centrifugal spread in a snake-like pattern occurs over
months to years. Treatment with steroids or immunosuppressive agents has had variable
success.

Inflammation in Behçet's disease
o
affects the anterior and posterior segments and is generally a bilateral process.
o
Recurrent explosive inflammatory episodes are typical with active episodes that
range from 2 to 4 weeks.
o
A chronic, lingering inflammatory stage typically does not develop.
o
A nongranulomatous anterior uveitis with formation of a transient hypopyon is
common.
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
Dhaval Patel MD
o
Posterior inflammation is characterized by recurrent vascular occlusive episodes
with retinal hemorrhage and vitreous inflammation. The inflammation is typically
confined to the retina and retinal vasculature. Choroidal involvement is rarely seen.
o
The retinitis of Behçet's disease is very suggestive of a viral retinitis and must be
considered in the differential.
Toxoplasmosis drugs
o
Pyrimethamine actually inhibits dihydrofolate reductase.
o
Sulfadiazine blocks the production of dihydrofolate from para-aminobenzoic acid.
o
Clindamycin is an antibiotic that can effectively kill Toxoplasma organisms.
o
Systemic and periocular steroids can be used in the treatment of ocular
toxoplasmosis in immunocompetent patients.
Fuchs' heterochromic iridocyclitis
o
an insidious, chronic intraocular inflammation that may not respond well to topical
corticosteroids.
o
Characteristic findings include diffusely distributed stellate keratitis precipitates and
mild anterior segment cell and flare with loss of iris crypts and detail.
o
Blue irides become more blue, and brown irides become less brown in cases of
Fuchs' heterochromic iridocyclitis.
o
Gonioscopy will reveal evidence of abnormal bridging vessels in the angle, although
neovascular glaucoma with angle closure does not develop.
o
A paracentesis of the anterior chamber may result in a small, splinter-shaped filiform
hemorrhage in the angle.
o
Fifty percent of patients with Fuchs' heterochromic iridocyclitis develop cataracts;
60% develop glaucoma.
o
Cataract surgery is not associated with any higher rate of vitreous loss or posterior
capsular rupture compared to normal eyes.
o
No posterior synechia, no increased risk of CME after cataract surgery
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Dhaval Patel MD
Iris mammilations are seen in
o
Nevus of ota
o
NF-1
o
Peter‘s
o
Axenfield Reiger‘s

Gordon‘s dictum for systemic steroids in uveitis – ―Use enough, soon enough, taper and
discontinue‖

Although syphilitic uveitis may mimic any other form of uveitis, intermediate uveitis is a
distinctly uncommon presentation.

Rod dysfunction seen in birdshot retinochoroidopathy leading to electroretinogram reveals
diminished scotopic responses.

Cystoid macular edema is not typically seen in patients with Vogt-Koyanagi-Harada
syndrome.

Diffuse unilateral subacute neuroretinitis DUSN is thought to be caused by numerous
different types of roundworms. Baylisascaris species have been implicated most
consistently.

Polymyalgia rheumatica is an inflammatory condition but it does not manifest as scleritis.

Primary intraocular lymphoma: leopard skin pattern of yellowish retinal pigment epithelium
and subretinal infiltration of lymphomatous cells are typically seen in patients over the age of
70 years
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
Onchocerca volvulus infection results in widespread dissemination of the microfilarial
larvae. These microfilaria can be seen swimming in the anterior chamber. The live
organisms may cause a mild uveitis and obstruct the trabecular meshwork; however,
dead organisms incite a vigorous inflammatory reaction, which causes much more
ocular damage.

An eosinophilic granuloma occurs with Toxocara intraocular infection. On
histopathology, the reaction may be so vigorous that the Toxocara organism may not be
visible.

Retinal antigens to induce EAU (Experimental Anterior Uveitis)

o
retinal S-antigen, also known as ―arrestin,‖ found in the photoreceptor outer
segments and in the pineal gland of some species; it competes with transducin for
rhodopsin in its photoexcited and phosphorylated state
o
interphotoreceptor retinoid-binding protein (IRBP), a major soluble protein in the
interphotoreceptor matrix
o
rhodopsin, a well-defined transmembrane protein of rod outer segments,
participating in visual transduction
o
recoverin, a calcium-binding protein that selectively localizes to the retina and pineal
gland, associated with cancer-associated retinopathy
Combination therapy with cyclosporine A, azathioprine and prednisolone was first
described by Hooper and Kaplan to control inflammation rapidly and promote visual
recovery in five patients with bilateral serpiginous choroiditis.

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Strabismus

The Bruckner test is a bilateral red reflex test, and if strabismus is present the brighter reflex
is in the deviated eye. This is because the light reflects from peripheral retina in the
deviated eye. Because there is less pigment in the peripheral retina than the macula,
there is more reflection of light from the peripheral retina of the deviated eye.

Alexander‘s law: Jerk nystagmus, usually increases in amplitude with gaze in direction
of the fast phase

Enthesiotomy: tenotomy and reattachment of muscle. It is done as nystagmus surgery.

The inferior and superior obliques are abductors of the eye in synergy with the lateral
rectus. The superior, inferior, and medial recti are all adductors.

A very important thing to understand about Moebius is that many other characteristics have
been found in patients who have the signal features of lack of abduction (or in some cases,
gaze palsy) and weakness of the facial muscles. These include: deafness, webbed fingers
or toes, supernumerary digits, defects in the muscles of the chest (Poland syndrome),
neck and tongue, missing fingers or toes and more. Because of the wide list of associated
features some would prefer to call this the Moebius sequence.

The parieto-occipital lobe controls the slow pursuit component, whereas the frontal lobes
control the saccadic component.
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Dhaval Patel MD
Exception to Sherrington‘s law: DRS, Retraction nystagmus
Exception to Hering‘s law: DVD

Several ocular and systemic anomalies have been associated with DRS: cataracts, iris
anomalies, Marcus Gunn jaw winking, microphthalmos, crocodile tears, Goldenhar's
syndrome, maternal thalidomide use, and Klippel-Feil syndrome.

There are three and possibly 4 classes of CFEOM that are genetically defined and have
different characteristics.
Class 1 has aligned eyes in down gaze which become esotropic on attempted up gaze.
Class 2 characterized by limited up gaze, ptosis and exotropia.
Class 3 is a milder form that can be a mixture of class 1 and 2 and may be unilateral. A new
classification of CFEOM called Turkel has an added finding of missing fingers. CFEOM is a
rare genetic disorder that results in varying degrees of inability to look up along with ptosis
and a chin up head posture. Treatment of any of the classes of CFEOM presents a
significant challenge and is usually done in stages.

Large vertical fusional amplitudes (>5 prism diopters) and facial asymmetry from
childhood headtilting suggest a decompensated congenital lesion.

In case of Restrictive Myopathy, A rectus muscle should never be resected but only
recessed.

Positive forced ductions indicate a restrictive process that may be caused by thyroid eye
disease, blow-out fractures, fat adherence syndrome, and Brown's syndrome, among
others.

Amblyopic eye functions better in mesopic condition.

A strabismic deviation can be neutralized by orienting an appropriate power prism with the
apex in the same direction as the deviation.
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
A prism diopter is defined as the amount of deviation of a light by the prism measured at
100 cm.

Prism power can be represented by vectors and added as this mathematical entity.

All rays parallel to the lens axis will converge on the secondary focal point whose location
can be calculated as 100 cm/Power = distance cm.

extraocular muscle is commonly involved in a dog bite:
The superior oblique muscle: This result from direct trauma (from the lower teeth of the dog)
to the trochlear causing paralysis of the superior oblique muscle and a Brown's syndrome
due to scarring. This condition is also called dog-bite syndrome or canine tooth syndrome.

The normal range of fusion as measured from 0° on the major amblyoscope is that of 30-35
convergence, 5° of divergence and 3-4 of vertical vergence.

Incidence of amblyopia in myopia is much less almost unknown for the reason that
myopia at least sees the near objects more clearly than in hypermetropia where all
accommodation reserve is up for distance and he neither sees dist/ance nor see near
objects clearly. Therefore, near vision stimulus is not deprived in myopia.

4-PD base-in prism test  differentiates convergence insufficiency [near vision improves]
from accommodative insufficiency [near vision worsens]

Faden: The lever arm of the muscle is weakened thus decreasing its action. Best for
MR and not for LR. (as MR has 6.0 mm arc of contact, LR has 15 mm arc of contact.)
o
Non accomodative convergence excess esotropia
o
Nystagmus blockade syndrome
o
Paralytic strabismus
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
o
Duane retraction syndrome
o
Dissociated vertical deviation
Dhaval Patel MD
Hummelsheim‘s procedure: For LR palsy
Lateral halves of sup and inf recti are dissected and reinserted near LR insertion

Jensen‘s procedure: For LR palsy
Lateral halves of sup and inf recti and upper and lower halves of LR dissected free

In the presence of microtropia "with identity," the cover test result is negative but the 4
prism diopter base-out test reveals a foveal suppression scotoma in one eye that
generally is also amblyopic.

The limbal incision for squint surgery may be done at the limbus for MR-LR-IR - but allow
a 1.5 to 2.0 mm "cuff" for SR to avoid increasing pannus at superior limbus.

A compensatory head posture with the chin elevated and pointing toward the opposite
shoulder permits fusion in Brown syndrome.

Pleoptoscope: Opthalmoscope fitted with a projected fixation target.

o
Used for Small-angle strabismus , with fixation anomaly and amblyopia.
o
It can also be treated by Occlusion of the amblyopic eye, followed by foveal
stimulation. Rotating blue polarised light, light ablation of the fixation zone followed
by repetitive foveal stimulation. Treatment unlikely to be successful if the other eye
has normal vision.
Bielschowsky phenomenon: Downdrift of occluded eye as increasing neutral density filters
are placed over fixating eye in dissociated vertical deviation (DVD)
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
Dhaval Patel MD
DVD
o
present in 60% to 80% of patients with congenital esotropia.
o
DVD is usually bilateral and asymmetric.
o
The etiology is unknown but appears to be associated with an early disruption of
binocular development. Thus, high-grade stereopsis and bifoveal fixation are not
seen.
o
During times of visual inattention, the nonfixating eye slowly drifts up, extorts, and
abducts without a corresponding hypotropia of the fellow eye on alternate cover
testing. This is the hallmark of this disorder—it does not obey Hering's law.
o
DVD can simulate Inferior Oblique Overaction (IOOA) in side gaze when the nose
acts as an occluder. The hyperdeviation in DVD is of the same amount in adduction,
abduction, and primary position. This is in contrast to IOOA, in which the
hyperdeviation is greatest in its field of action.
Duane Retraction Syndrome (DRS) can be associated with Anisometropia, coloboma,
microphthalmos and heterochromia.
o
Two syndromes associated with this are: Goldenhar and Wildervanck syndrome.
The child can have a hearing or a speech disorder as well
o
The phenomenon commonly seen is the leash phenomenon and a severe leash is
treated with Y splitting of the lateral rectus muscle with posterior fixation sutures of
the lateral rectus muscle.

A right superior oblique palsy can result in vertical or torsional diplopia. Vertical diplopia
may be treated with either ipsilateral inferior oblique myectomy or anterior transposition,
contralateral inferior rectus recession or ipsilateral superior oblique tuck (sometimes in
combination}. Torsional diplopia can be treated with anterior transposition of the superior
oblique muscle.

Differentiation of unilateral from bilateral fourth nerve palsy is essential for successful
surgical management.
o
Features of unilateral fourth nerve palsy include: head tilt to the affected side,
unilateral hypertropia on lateral gaze, less than 5 of exocyclotorsion.
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o
Dhaval Patel MD
Features of bilateral fourth nerve palsy Include: chin down posture with eyes
looking up, alternating hypertropia on right and left gaze respectively, large
exocyclotorsion of more than 10

Infantile esotropia has large angle esotropia. Binocular single vision is usually poor
despite early treatment. The temporal-to-nasal movement is usually better than nasal-totemporal movement on optokinetic testing. Dissociated vertical deviation and inferior oblique
overaction are common and have been reported in about 90% of patients. Post-surgical
esotropia may be caused by an accommodative component.

Optokinetic response tests the pursuit and saccadic movements. When the drum is
rotated to the right, the pursuit movement is mediated by the right parietal lobe and the
saccadic movement by the right frontal lobe, i.e. the optokinetic response tests the
pursuit and saccadic movement on the side towards which the drum is moving.
Parinaud's syndrome causes up-gaze palsy and vertical rotation of the drum will elicit
convergence retraction nystagmus. In a patient with a frontal lobe lesion, there may be
deviation of his or her eyes to the side of the lesion. However, provided the contralateral
frontal lobe is intact, rotating an optokinetic drum away from the side of the frontal lobe will
elicit a response.


How to dissociate two eyes?
o
Septum so that one half of the field is seen by one eye exclusively and the other by
the other eye.
o
Two tubes one in front of each eye.
o
Red-green glasses, which are complementary in the sense that with red filter sees
only red light other with green filter sees only green.
o
Polaroid dissociation, each eye views through polaroid filters each one at 90
degrees to each other.
o
Bagolini's striations, a spot light scattered striations, the two glasses set at 90° to
other.
Mary Maddox: English Strabismologist
o
Maddox tangent scale
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o
Maddox rod
o
Maddox hand frame: uniocular and binocular
o
Maddox Wing
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
The torsional eye movements occur around the anteroposterior or Fick's Y axis. This does
not pass through the centre of cornea but at a point on the lateral limbus as shown by
Linwong.

Magician Forceps Phenomenon: On passive adduction of the dominant eye, the other
eye's exodeviation gets corrected. This reflex is present even in the dark. This reflex is
abolished by deep retrobulbar anesthaesia.

Phospoline iodide: medicine that affects accommodative convergence and used as a
therapy sometimes.

Isolated agonist model was described by Duane for eye movements. However, it is
important to remember that during eye movements, all six extraocular muscles are in some
state of contraction or relaxation, and it is strictly hypothetical to discuss the movement of
the eye as if only one muscle contracts.

Paired Antagonist Model was described by Boeder.

Aging chages in EOM

o
Both horizontal rectus muscles are displaced inferiorly with age (MR >> LR)
o
The superior rectus and inferior rectus muscles do not change locations
o
greater variety in fiber sizes, increased connective tissue in the muscle, increased
adipose tissue in the bundles, deposits of lipofuscin, and degenerative changes.
amblyopia ex anopsia: amblyopia due to media opacity
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
Antepodean Strabismus: It is present when the patient has esotropia while fixing with
one eye and exotropia when fixing with the other eye. This occurs with anisometropia
and an improperly corrected refractive error. Some cases are believed to be due to unequal
accomodation.

Principle of Faden: Point of posterior fixation is new insertion for action. As antagonist
entire muscle acts. Therefore limits muscle action only in field of its action.

Adherence syndrome: The orbital fat is separated from the globe by Tenon‘s capsule. If an
accidental opening is made in the portion of Tenon‘s capsule that separates the orbital fat
from sclera, orbital fat may be pressed through the opening and adhere to the globe. This
adherence often results in limited eye moments. It is best treated by prevention. The orbital
fat comes forward around the equator of the globe to within 10 mm of the limbus. Care
should be taken not to cut Tenon‘s capsule more than 10 mm from the limbus.

Only fusional convergence (i.e. overcoming exophoria) dampens nystagmus.
Accommodative convergence does not dampen nystagmus and even works against the
patient by increasing accommodative demands and may cause the near point to recede with
reduced visual acuity at near. So minus glasses does not improve nystagmus.

Centre for voluntary convergence: Frontal oculogyric area (area 8)
Centre for reflex convergence: peristriate area of occipital cortex
Lower convergence centre: nucleus of Perlia

NPC is usually <8 cm.
Normal convergence amplitude is 10.5 Ma. (0.5 prism diaoptre correspond to 1 Ma)

Convergence insufficiency is NPC > 11 cm or inability to maintain 30 degree convergence
on synaptophore.
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
In class 7 SO palsy, traumatic paresis plus restriction of relaxation of the superior oblique,
also known as the canine tooth syndrome because it is most frequently caused by a dogbite injury to the trochlear area, requires surgery to correct the Brown syndrome first, with a
subsequent attempt at correcting paresis of the superior oblique if possible.

Cooper's Dictum: Stretched scar may have been the mechanism behind Cooper's report of
failure of advancing previously recessed medial recti for consecutive exotropia. He
advocated instead recessing the antagonist lateral recti. This principle is known as
Cooper's Dictum.

Liquid crystal glasses have recently been developed as a new treatment for amblyopia.
They provide an electronic, controlled, intermittent occlusion of the sound eye allowing for
visual stimuli input to the amblyopic fellow eye. A liquid crystal glass in the sound eye is
used as an intermittent flickering shutter switched between ―on‖, or occlusion and ―off‖ or
light transmission. The flickering sequence can be adapted to the depth of amblyopia, the
length of treatment, and the patient‘s age.

CAM Vision Stimulator - Amblyopic eye is stimulated by slowly rotating, high contrast,
square wave gratings of different spatial frequencies for 7 minutes but the results are not
much promising.

Hertle Dell‘ Osso proceduce: tenotomy and re attachment (rectus muscle) surgery done
for nystagmus.

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Neurophthalmology

Location of Lesion:
o
WEBINO (wall-eyed bilateral internuclear ophthalmoplegia): riMLF and 3rd CNN
(Involvement of the paired medial rectus subnuclei)
o
Internuclear ophthalmoplegia: Ipsilateral MLF, i.e. the same side as the eye that
has adduction restriction.
o
Down-gaze palsy: riMLF
o
The lesion for skew deviation is in the brain stem but the exact location is
unknown.
o
One and a half syndrome - ipsilateral MLF and 6th CNN

Aberrant regeneration of the oculomotor nerve occurs in ‗surgical‘ third nerve palsy and
not in 'medical' third nerve palsy such as diabetes mellitus or hypertension. Retraction of the
upper lid on down-gaze is called pseudo von Graefe's sign and miosis of the pupil on
adduction is termed pseudo Argyll-Robertson pupil.

Kollner‘s Rule:
o
Retinal Disease causes Blue-yellow defects

o
Optic nerve disorders causes Red Green defects


Exceptions: Stargardt‘s and Cone dystrophy
Exceptions: Glaucoma and autosomal dominant optic atrophy
The Pulfrich phenomenon probably reflects delayed conduction in the demyelinated nerve.
Oscillating objects perceived by the affected eye appear to be behind the image seen with
the healthy eye, simulating three-dimensional movement where there is only movement
within one plane.
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
Cogan's lid twitch - overshoot on moving from depression to primary position in
myasthenia.

Heidenhain variant of Alzheimer disease of CJD causes visual hallucinations.

lce test- reduced ptosis after ice pack applied for 2 minutes.

Alternating Anisocoria:


o
Aka See-saw anisocoria
o
One pupil larger in light and other is larger in dark  3rd nerve palsy and horner‘s
syndrome
Benign alternating anisocoria:
o
discreet entity not found in normal subjects but which may be present in more than
one member of a family
o
some patients in whom apparently physiological anisocoria appears to change from
side to side with the larger pupil appearing on occasion in one eye and on occasion
in the fellow eye
Alternating Horner‘s syndrome:
o
Cervical cord lesions, syringomyelia, radiation myelopathy, shy-daeger syndrome

Horner syndrome with 6th nerve palsy together: cavernous sinus lesion

Reasons for Light near dissociation 
o
30 times more fibres serve miosis through accommodation than through light.
o
Aberrant innervation of iris sphincter by accommodative neurons
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Causes:
Unilateral
Afferent conduction defect
Adie pupil
Herpes zoster ophthalmicus
Aberrant regeneration of the 3rd nerve
Bilateral
Neurosyphilis- Argyll Robertson pupils
Type 1 diabetes
Myotonic dystrophy
Parinaud (dorsal midbrain) syndrome
Familial amyloidosis
Encephalitis
Chronic alcoholism

There is no clinical condition in which the light reflex is present but the near response absent
but vice versa is not true.

The midbrain centre for the near reflex is probably located more ventrally than the
pretectal nucleus and this is why compressive lesions such as pinealomas, preferentially
involving the dorsal internuncial neurones involved in the light reflex, spare the near reflex
fibres until later.

Pupillary sphincter has atlease 20 segments each of this innervated by different branches of
short ciliary nerve.

Wernicke‘s hemianopic pupil occurs in  optic tract lesion
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
In afferent (sensory) lesions, the pupils are equal in size. Anisocoria (inequality of pupillary
size) implies disease of the efferent (motor) nerve, iris or muscles of the pupil.

blurring of vision worse on waking:
Impending central retinal vein occlusion
Papillophlebitis
NAION

Reverse RAPD: When the pupil of the involved eye is nonreactive or nonfunctional, observe
the fellow, normal eye for a ―reverse‖ RAPD (dilation when light is on nonreactive eye,
constriction when light is shined on reactive eye).

Morning glory disc is a congenital coloboma of the disc or glial tissue of the disc head.
o
It may be associated with congenital forebrain anomalies including basal
encephalocele, frontonasal dysplasia and NF-2.
o
May be associated with the papillorenal syndrome, a PAX2 gene mutation.
o
Approximately 30% patients can have subsequent serous RD.
o
PHACE syndrome characterized by posterior fossa brain malformations, large facial
haemangiomas and cardiovascular anomalies. It almost exclusively affects females.
It is also associated with morning glory disc.

Ophthalmic artery obstruction usually does not produce a cherry-red spot due to underlying
choroidal ischemia.

Approximately half of the fibers of the optic nerve decussate in the optic chiasm, and the
input to each of the parasympathetic nuclei in the brain stem remains equal. Therefore,
relative afferent pupillary defects do not cause anisocoria because any changes in light
input are distributed equally to both pupils.
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
Retinal migraine: ―Ocular‖ migraine, rare; monocular scotoma or visual loss for minutes to
an hour due to retinal or optic nerve ischemia.

Willebrandt‘s knee: Inferonasal optic nerve fibers that decussate in chiasm and loop into
contralateral optic nerve before traveling back to optic tract

Inadvertent ocular exposure to anticholinergic agents also has been reported. Patients using
scopolamine patches have been noted to have self-limited mydriasis, which has been
dubbed ―cruise ship anisocoria‖.
Anticholinesterases- flea collar anisocoria

Oculodigital sign of Franceschetti is seen in Leber congenital amaurosis. They also
have severe visual impairment from birth. Vision remains stable or worsens slowly over time.
These individuals tend to be hyperopic and have photophobia. They also are likely to
engage in eye poking or oculo-digital massage, presumably to create light flashes. This
behavior is called blindism.

Collier‘s sign: Bilateral eyelid retraction associated with midbrain lesions

Clonazepam and suboccipital craniotomy have been used in the treatment of downbeat
nystagmus in patients with Arnold-Chiari malformation.

The differential diagnosis for posterior ischemic optic neuropathy (PION) should include
radiation optic neuropathy, status post-coronary artery bypass graft, anemia, acute systemic
hypotension, giant cell arteritis (GCA), and syphilis.
Well-controlled essential hypertension is associated with anterior ischemic optic neuropathy
(AION) but not PION.

In Giant cell arteritis: CRP > 2.45 mg%, ESR >47 mm/hour
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
Optic disc drusen may be associated with retinitis pigmentosa, pseudoxanthoma
elasticum, angioid streaks and allagile syndrome.

In general, optic nerve compression >1 cm posterior to the globe does not cause disc
edema.

A skew deviation is a motility disturbance with a vertical component that does not have a
pattern consistent with a discrete muscle underaction or nerve palsy. They are generally
due to supranuclear or vestibuloocular dysfunction and generally reflect brainstem
disease. They are typically comitant but not always.

Although transient changes in vertical eye movements and slowing of vertical saccades can
result from lesions of the paramedian pontine reticular formation, nuclei crucial for the
initiation of vertical eye movements are the rostral interstitial nucleus of the medial
longitudinal fasciculus (riMLF) and the interstitial nucleus of Cajal (INC).

Isolated sixth nerve palsy in children is most commonly attributable to postviral
inflammation occurring 1 to 3 weeks following a nonspecific viral illness of the upper
respiratory tract. Recovery is generally complete and occurs within 10 to 12 weeks.

Czarnecki‘s sign: Segmental pupillary constriction with eye movements due to aberrant
regeneration of cranial nerve III

Medial rectus contracture is distinctly uncommon in Duane's syndrome. In congenital
sixth nerve palsy, it is quite common and results in esotropia in primary position.

Exotropia in primary position can occasionally occur in association with a bilateral INO (A
lesion that involves both medial longitudinal fasciculi near their junctions with the third nerve
nuclei) resulting in a syndrome called wall-eyed bilateral INO - WEBINO.
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
Sixth nerve palsy caused by an intracavernous lesion may present as abduction palsy
plus miosis because within the cavernous sinus, sympathetic branches of the paracarotid
plexus join the sixth nerve briefly.

In the cavernous sinus, cranial nerves III, IV, and V are relatively protected within the
walls of the sinus, but cranial nerve VI runs in the middle of the sinus and is more prone
to injury.

Horizontal saccades originate in the contralateral frontal lobe, but either hemisphere can
produce ipsilateral saccades if the other hemisphere is damaged.

Oculomotor apraxia is an inability to initiate voluntary horizontal saccades. Congenital
oculomotor apraxia is characterized by striking compensatory head movements, and
acquired lesions (e.g., resulting from bilateral frontal lobe strokes) usually produce defects in
initiation of bidirectional saccades—patients may blink to break fixation and then turn their
head to fixate on something else. Pursuits remain relatively unaffected.

Opsoclonus consists of nonstop, random, directionally unpredictable saccades.
Ocular flutter consists of spontaneous groups of back-and-forth horizontal saccades
that may occur during fixation or at the end of a normal horizontal saccade.
Both ocular flutter and opsoclonus may be associated with malignancy, such as metastatic
neuroblastoma in children or small cell cancer of the lung in adults. These eye movements
may be the first presenting sign of cancer. Multiple sclerosis (MS) also can cause ocular
flutter.
Square-wave jerks are a microsaccadic fixation disturbance associated with cerebellar
diseases of various kinds.
Ocular motor dysmetria is a back-and-forth saccadic motion about the point of fixation that
occurs following an otherwise normal saccade. It is felt to represent ―overshooting‖ of the
intended fixation point.
Ocular bobbing is most commonly seen in comatose or quadriplegic patients with large
infarcts or brainstem hemorrhages.
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
In progressive supranuclear palsy (PSP), downward gaze is generally affected,
becoming smaller and slower. Saccades are affected more than pursuits. This is in
distinction to the dorsal midbrain syndrome, in which upward saccades are generally
affected.

The period between detection of movement and the beginning of smooth pursuit (for
tracking) is between 125 and 135 milliseconds. Initiation of saccadic movement requires
from 150 to 200 milliseconds from the first perception of a target. The latency in
generating a pursuit movement is shorter than that for a saccade movement.

Skew deviation is, by definition, a vertical misalignment of gaze that cannot be assigned to
a single nerve or muscle weakness. In the presence of an internuclear opthalmoplegia
(INO), the hypertropic eye is often on the same side as the adduction deficit (medial rectus
dysfunction).

Upward gaze paresis, light-near dissociation, lid retraction, accommodative abnormalities,
and convergence-retraction nystagmus, fixation instability, small-amplitude skew deviation,
and papilledema (if ventricular outflow has been compromised) are all features of the dorsal
midbrain (Parinaud's) syndrome. Furthermore, skew deviation and papilledema may be
seen, depending on the etiology. Lid retraction—the Collier sign—may worsen with
attempted upgaze. Convergence-retraction nystagmus is also a response to an effort at
upgaze that triggers medial rectus contractions. Hence, this form of ―nystagmus‖ is
worsened by upward optokinetic nystagmus (OKN) testing.

Monocular nystagmus has been associated with chiasmal and hypothalamic gliomas. It is
also seen in blind eyes, multiple sclerosis (MS), and spasmus nutans—a transient, fastbeating, but low-amplitude nystagmus found during the first 5 years of life.

The classic triad of spasmus nutans includes monocular or dissociated small-amplitude
nystagmus, head bobbing, and torticollis. The differential diagnosis for this disorder
includes patients with chiasmatic gliomas and subacute necrotizing encephalomyopathy.
Features of these two disorders may include optic atrophy, irritability, vomiting, and
increased intracranial pressure. Spasmus nutans should be considered only after these two
disorders are excluded. Spasmus nutans usually disappears within 2 years of onset.
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
Alexander's law describes the increased frequency and amplitude of nystagmus
movements accompanying gaze in the direction of the fast-beating component. Of the
various forms of nystagmus, downbeat nystagmus most frequently violates Alexander's law.

Upbeat nystagmus can be caused by lesions of the anterior vermis and lower brainstem,
as well as drugs and Wernicke's encephalopathy.
Downbeat nystagmus may be localized to anatomic structures at the craniocervical
junction (e.g., Arnold-Chiari malformation) and may be seen in certain intoxications (alcohol,
lithium).
Vestibular nystagmus has its etiology within the vestibular system.
Periodic alternating nystagmus also can localize to the craniocervical junction but may be
seen in other forms of posterior fossa disease.
Seesaw nystagmus results from third ventricle tumors or diencephalic lesions involving the
connections to the interstitial nucleus of Cajal (INC) and is therefore the most localizing.

Vergence eye movements are felt to have a pathway of their own for stimulating the
brainstem motor nuclei. Saccades originate in the contralateral frontal lobe, whereas
pursuits arise in the ipsilateral parietal lobe.

Marcus Gunn's ―jaw-wink‖ reflex is an example of synkinesis (abnormal innervation
connecting two groups of normally unrelated muscles, such that they contract together), but
it is not synkinesis because of aberrant regeneration, which usually follows a peripheral
neuropathy or trauma to the nerve. The ―jaw-wink‖ is a congenital/neurogenic phenomenon.

three most common causes of facial nerve overactivity:
1. only essential blepharospasm is believed to be related to basal ganglia dysfunction.
2. Compression of the facial nerve in the cerebellopontine angle by anomalous vessels
has been demonstrated in 90% of cases of hemifacial spasm. Tumors in the
cerebellopontine angle also can cause hemifacial spasm.
3. Facial myokymia is caused by disease in the pons involving the facial nucleus or
fascicle. The most common causes include multiple sclerosis (MS) in adults and
pontine glioma in children.
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
The afferent pupillomotor fibers exit the optic tracts just before the lateral geniculate body
(LGB); they do not pass through the LGB. Although postganglionic pupillomotor fibers in the
sympathetic pathway do arise from the superior cervical ganglion, the sympathetic pathway
leading to these fibers is thought to originate in the posterior hypothalamus. In addition,
postganglionic sympathetic fibers enter the orbit with the ophthalmic division of the
trigeminal nerve through the superior orbital fissure. The consensual pupillary response is
seen because of decussation at the pretectal nuclei. Were the chiasm split in half,
consensual responses would be preserved.

In uncal herniation and basilar meningitis, pupil dilation may be the only sign of third
nerve palsy. In the case of a cerebral aneurysm, the pupil is usually involved, along with
other functions of the third nerve. If the pupil is not involved, it is less likely that an aneurysm
is the cause of the palsy. Total oculomotor palsy with a spared pupil in elderly patients
usually suggests a microvascular etiology.

Horner's syndrome is defined as ipsilateral ptosis and miosis. Ptosis is secondary to lack
of Müller's muscle function. Anhidrosis may or may not be present.
Localization of the lesion in Horner's syndrome is part of the clinical workup and sometimes
guided by the extent of anhidrosis.
First-order lesions (central nervous system) cause ipsilateral anhidrosis of the entire body.
Second-order lesions (Pancoast's tumor, neck trauma) cause ipsilateral facial anhidrosis.
Third-order lesions (carotid dissection) cause anhidrosis only around the affected eye or
none at all.
1. In response to 4% cocaine, a normal pupil will dilate, but a Horner's pupil will dilate
poorly.
2. Hydroxyamphetamine (Paredrine) will cause a similar response in preganglionic
Horner's syndrome only.
Painful Horner's syndrome may be caused by many disorders (neck trauma, migraine,
cluster headaches), but spontaneous dissection of the common carotid artery must be ruled
out with angiography or magnetic resonance imaging (MRI)/magnetic resonance
angiography (MRA)
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
It is important to examine the optic disc carefully in all patients with suspected central
serous retinopathy. (a/w Optic Disc Pit)

The temporal 30 degrees of a binocular visual field is perceived by the nasalmost retina of
the ipsilateral eye only. These ―temporal crescents‖ are represented in the anterior-most
occipital lobe. Therefore, a lesion in this area will produce a monocular visual field defect in
the far temporal periphery of the contralateral eye, the so-called temporal crescent
syndrome. For example, a right anterior occipital lobe lesion would produce a far temporal
field defect in the left eye. Similarly, a right posterior occipital lobe lesion may spare the far
temporal field in the left eye.

Inferior nerve fibers from the superior retina course anteriorly in Meyer's loop; therefore,
lesions affecting Meyer's loop will result in pie-in-the-sky defects contralateral to the lesion.

Although loss of spontaneous venous pulsations is an early sign of papilledema,
approximately 20% of normal patients lack venous pulsations.

Pseudotumor cerebri is characterized by (i) increased intracranial pressure on lumbar
puncture, (ii) normal neuroimaging studies (although the ventricles may be small), and (iii)
normal cerebrospinal fluid (CSF). Papilledema need not be present for the diagnosis.

The various ways to differentiate the NAION from optic neuritis include (i) the absence of
pain with eye movement, (ii) the age group affected, and (iii) delayed optic disc filling
present in 75% of NAION cases (whereas filling should be normal in optic neuritis).

Collateral vessels (optociliary shunt vessels) at the disc connecting the retinal and
choroidal vascular systems may be seen in association with optic nerve meningioma, central
retinal vein occlusion (CRVO), sphenoid wing meningioma, long-standing primary openangle glaucoma (POAG), optic gliomas, or chronic papilledema.

Patients with ―papillophlebitis‖ have normal or near normal visual acuity. It may be a form
of incomplete central retinal vein occlusion (CRVO) and usually resolves spontaneously
within 12 months.
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
Optic nerve hypoplasia is seen with greater incidence in children of diabetic mothers and
following fetal exposure to antiepileptic medications, quinine, or lysergic acid diethylamide
(LSD). Optic nerve hypoplasia, particularly bilateral involvement, has been associated with
other midline developmental anomalies—that is, absence of the septum pellucidum and
hypothalamic-pituitary abnormalities. Endocrine dysfunction is manifested as hypoglycemic
seizures and growth retardation. This combination of clinical findings is known as
DeMorsier's syndrome in 10% (septo-optic dysplasia).

Babies of IDDM mothers more likely to have superior segment hypoplasia giving rise to
inferior field defects.

Nonsecreting pitutary tumors often present with visual field loss, whereas secreting
tumors present with endocrine dysfunction. An exception is prolactin-secreting tumor in
male patients because the decreased libido and impotence are often not reported early in
their course.

Bitemporal macular hemianopia can only arise from compression of the posterior
chiasm. Although most lesions responsible for this compression are parasellar, a lesion
distant from this site (e.g., a tumor at the base of the brainstem) also may lead to chiasmal
compression. This occurs if the lesion causes obstructive hydrocephalus, which enlarges
the third ventricle, compressing the chiasm.

The most common location for a cerebral aneurysm with third nerve palsy is the junction
of posterior communicating artery and internal carotid artery. PCA-ICA

Third nerve aberrant regeneration never occurs with diabetic oculomotor neuropathy.
Aberrant regeneration of the third nerve implies another etiology, such as aneurysm, tumor,
inflammation, or trauma. Other classic findings of aberrant regeneration include persistent
vertical gaze limitation secondary to simultaneous contraction of superior and inferior recti,
and pupillary miosis with elevation, adduction, or depression.

The earliest loss of visual field in chronic papilledema is typically in the inferior nasal
quadrant.
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
Retinal and optic nerve lesions produce field defects that do not generally respect the
vertical midline. The presence of a field defect that respects the vertical midline should
always arouse suspicion of a neurologic lesion (e.g., cerebrovascular accident, tumor),
especially when the disc and field changes do not correspond.

The only location at which oculomotor superior division nerve palsy could occur without
affecting additional cranial nerves or the inferior division of cranial nerve III is in the orbital
apex.

The location of a lesion affecting the oculomotor nerve can be determined by the associated
neurologic deficits. An oculomotor nuclear lesion also involving the ipsilateral cerebral
peduncle causes contralateral hemiparesis (Weber's syndrome). Cranial nerve III palsy
with contralateral decreased sensation and contralateral tremor (red nucleus affected) is
Benedikt's syndrome.

The parasympathetic pupillomotor fibers controlling the pupil are found on the outside of the
oculomotor nerve and are the first to be injured with external pressure. Diabetic
microvascular insults affect the central fibers of the nerve to a greater degree than the outer
fibers, and as a result, pupil involvement is less common (<20%).

A contralateral relative APD would be present if the optic tract was damaged because
relatively more nasal fibers from the contralateral eye cross in the chiasm.

A relative afferent pupillary defect never causes anisocoria because the pupillary fiber
decussations in the chiasm and posterior commissure ensure equal efferent input to both iris
sphincter muscles.

Adie's tonic pupil is hypersensitive to parasympathomimetics and will constrict with
pilocarpine 0.1%.

The mnemonic COWS—cold-opposite-warm-same—helps to give the direction of the fast
phase of the nystagmus. Slow phase would be just opposite of fast phase.
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
Louis-Bar syndrome (ataxia-telangiectasia) is not associated with any CNS abnormalities
detectable with neuroimaging.

Uhthoff's symptom occurs with optic neuritis and is a decrease in vision with an increase in
body temperature. Exercise or hot showers may trigger this symptom.
Lhermitte's sign is the electric shock sensation with neck flexion and is found in patients
with multiple sclerosis.
The Riddoch phenomenon occurs in patients with cortical blindness who are able to
perceive objects in motion, but cannot see stationary objects.

A bilateral medial occipitotemporal lesion causes prosopagnosia, the inability to
distinguish faces.

The nuclei controlling the superior rectus and superior oblique muscles have crossed
projections.

Horner's syndrome can be confirmed with the cocaine test and damage to the second order
neuron is supported with the hydroxyamphetamine test.
In the cocaine test, 4% (not 10% as some advocated) cocaine is instilled into both eyes.
Horner's pupil dilates little or none at all. Reuptake of the norepinephrine occurs normally in
the synaptic cleft. Cocaine blocks the reuptake, causing rapid accumulation within the
synaptic cleft resulting in dilation of a normal pupil. The presynaptic nerve endings in
Horner's syndrome have impaired sympathetic tone and therefore respond poorly or none at
all to the effect of cocaine.
Hydroxyamphetamine stimulates the release of norepinephrine from the presynaptic nerve
endings resulting in dilatation of the pupil. If the nerve is damage, the nerve will not release
norepinephrine as is the case with third order neurone lesion. In the case of first and second
order neurone lesion, the pupil will dilate as the third order neurones are intact.

Optic Pit commonly involves temporal part of the disc.
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Anton‘s Syndrome: denial of Blindness

Metabolic acidosis is the hallmark of optic neuropathy induced by methanol.

The optic nerve is generally myelinated to the lamina cribrosa 4 to 6 months before foveal
maturation.

It should be emphasized that in afferent (sensory) lesions, the pupils are equal in size.
Anisocoria (inequality of pupillary size) implies disease of the efferent (motor) nerve, iris or
muscles of the pupil.

Visual evoked potentials (VEPs) document 20/20 acuity by the age of 6 to 8 months.
Preferential looking testing (PLT) cannot document 20/20 until 24 to 30 months.

superior rectus and medial rectus are closely attached to the dural sheath of optic
nerve, at their origin. This accounts for the characteristic pain felt on moving the eyeball up
and in, in a case of retrobulbar neuritis.

Hemifacial spasm is differentiated from blepharospasm in that it is unilateral and the
spasm will persist during sleep. Unlike in blepharospasm, oral sedatives are usually of
no benefit in hemifacial spasm. The pathogenesis is thought to be irritation along the course
of the facial nerve. Therefore, neuroimaging to rule out a mass or narrowing of the skull
base foramen is necessary. If imaging is negative, the usual therapy is botulinum toxin
injections to dampen the spasms of the offending muscles. Facial nerve decompression is
also helpful in patients with compression at a foramen or in whom a blood vessel crosses
over and compresses the nerve.

photostress recovery test:
to differentiate between macular and optic nerve disease. Patients who have a
maculopathy will take longer (90 to 180 seconds) to recover pretest vision after looking
into a bright light for 10 seconds. Patients with optic nerve disease will have a normal
recovery time (<60 seconds). The test is probably only valid for patients with vision
better than 20/80.
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Tests for factitious monocular blindness:
major loss: OKN, the rocking mirror test, and the base-up prism test, fogging refraction
minor loss: fogging refraction

intact oculovestibular reflexes in a patient with a gaze palsy implies a supranuclear
disturbance. If the vestibular system can drive the eyes in the direction of the paretic field of
gaze, the gaze paresis must be supranuclear in nature. Impaired oculocephalic
responses indicate that the infranuclear, end-organ function is responsible for the motor
disturbance.

In the setting of an upgaze paresis, upturning of the eyes on forceful opening of closed
eyelids implies a supranuclear lesion.

Although there is some redundancy of the optic nerve within the orbit, the intracranial optic
nerve has little ―slack.‖

53% of the retinal ganglion cells cross in the chiasm (this difference is occasionally
important clinically).
The macular fibers constitute a large portion of the optic chiasm and most decussate in the
posterior chiasm.
The inferior nasal retinal fibers cross in the anterior chiasm and were thought to loop
anteriorly in the contralateral optic nerve before traveling posteriorly, leading to the term
Wilbrand's knee. It is now thought that Wilbrand's knee may be an artifact.
The chiasm lies approximately 1 cm (not 1 mm) above the anterior pituitary gland.

ipsilateral ganglion cells synapse in layers 2, 3, and 5, whereas the contralateral ganglion
cells synapse in layers 1, 4, and 6.

Inferior fibers of the optic radiations pass extremely close to the internal capsule.
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Parietal lobe lesions
o
Agnosia
o
Right-left confusion
o
slow-phase pursuit movements toward the ipsilateral side
o
hemianopia that are denser inferiorly
o
nondominant lobe: constructional and dressing apraxia
o
dominant lobe: GERSTMANN SYNDROME  agraphia, acalculia, left-right
confusion, finger agnosia
o
Asymmetric OKN
temporal lobe lesion
o
seizures
o
formed visual hallucinations
o
pie-in-the-sky defects contralateral to the lesion
occipital lobe lesion
o
unformed hallucinations
o
macular sparing
o
sparing of the temporal crescent
o
Occipital lobe infarcts can be associated with visual hallucinations, denial of vision
loss (Anton-Babinski syndrome), and the ability to perceive moving but not
static objects (Riddoch phenomenon).
o
OKN Sign?
80% of patients with cavernous sinus-dural fistulae will develop ocular hypertension.
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Nonarteritic anterior ischemic optic neuropathy (NAION) is far more common than arteritic
anterior ischemic optic neuropathy (AAION) (approximately 95% vs. 5%) and patients have
a lower mean age at diagnosis than patients with AAION (60 years vs. 70 years). It usually
occurs in a younger age group and may resemble optic neuritis.
The various ways to differentiate the NAION from optic neuritis include
o
the absence of pain with eye movement,
o
the age group affected, and
o
delayed optic disc filling present in 75% of NAION cases (whereas filling should be
normal in optic neuritis).
Although aspirin may prevent further strokes in patients with NAION, its effect on the
contralateral eye is unclear.

16% of patients with an initial attack of optic neuritis with a negative magnetic resonance
imaging (MRI) will develop multiple sclerosis (MS) at 15-year follow-up.
More than 50% of patients with three or more lesions that are visible on MRI will develop
MS at 15-year follow-up.

CSF in multiple sclerosis shows increased immunoglobulin/albumin ratio.

Imaging of choice in multiple sclerosis is MRI with FLAIR.

Optic nerve drusen occur almost exclusively in white individuals.

Best method for detecting decompensated congenital fourth nerve palsy is: vertical
fusional amplitude measurements.

Within the cavernous sinus, sympathetic branches of the paracarotid plexus join the sixth
nerve briefly. Sixth nerve palsy caused by an intracavernous lesion may present as
abduction palsy plus miosis.
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Congenital motor nystagmus has several features, including normal visual acuity,
paradoxic optokinetic nystagmus (OKN) (caused by the abnormal movements of nystagmus
appearing ―slow‖ and against the expected direction of target tracking), dampening by
convergence, and aggravation by fixation. Fortunately, oscillopsia (the sensation of the
world moving) is not normally a problem.

Bitemporal hemianopia may be seen in acquired seesaw nystagmus because the
posterior chiasm is most vulnerable to diencephalic lesions, which may provoke it.

Neurosarcoidosis: 7th CN > 2nd CN

The consensual pupillary response is seen because of decussation at the pretectal
nuclei. It will be preserved even if chiasma would be split in half from centre.!!
Whereas Marcus-Gunn Pupil is seen because of crossing at chiasma.

Four signs constitute complete Kearns-Sayre syndrome: (i) progressive external
ophthalmoplegia (PEO), (ii) mild pigmentary retinal degeneration, (iii) onset before 20
years of age, and (iv) heart block, potentially lethal and among the last signs to develop.
Some studies indicate that elevated cerebrospinal fluid (CSF) protein levels correlates with
the presence of heart block.

Although 75% of all myasthenics will have eye findings at presentation, only 33% to 50% will
have ocular myasthenia only. A higher percentage (90%) of patients with myasthenia gravis
(MG) will develop ocular symptoms during the course of the disease. Ptosis is the most
common. 5% of patients bwith Graves' disease will develop myasthenia gravis (MG) as
well. 10% of myasthenic patirnts have thymomas.

For a patient to be reassured that systemic disease is unlikely, ocular myasthenia should
remain localized for 2 years.

Patients with embolic central retinal artery occlusion (CRAO) are at great risk of myocardial
infarction (MI).
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Vertebrobasilar insufficiency typically causes binocular visual blurring or oculomotor
symptoms. Other symptoms of vertebrobasilar insufficiency include transient dysarthria,
drop attacks, photopsias, and hemisensory defects.

So-called tobacco-alcohol amblyopia seems to be seen only in heavy smokers/drinkers
with poor nutrition.

The development of diabetic papillopathy appears to be independent of serum glucose
levels. Diabetic papillopathy is classically seen in young adults with type 1 diabetes with
moderate to severe retinopathy (although it can be seen in patients with type 2 diabetes as
well). It is painless, and associated visual loss is generally mild. The disorder generally
resolves spontaneously.
Diabetic papillopathy does not leak on FFA.

In grave‘s ophthalmopathy, Systemic corticosteroids are thought to be effective only in the
acute congestive phase and not in the fibrotic period. Therefore, if no response is noted
within 3 weeks, systemic steroids should be tapered and another modality should be
considered.

Painful Horner's is an acute dissection of the internal carotid artery until proven otherwise.
The diagnosis of exclusion then becomes migraine if the angiogram is normal.

Aicardi's syndrome features mental retardation, lacunar retinopathy, and/or congenital
absence of the corpus callosum.

Precocious puberty may be a part of polyostotic fibrous dysplasia (Albright's syndrome).

The ―-triptan‖ antimigraine drugs are used for symptomatic relief of migraines but are
contraindicated in patients with basilar artery migraine.
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
Binding (not blocking) antibodies to acetylcholine receptors are found in 90% of patients
with generalized myasthenia gravis (MG).

drug-induced myasthenia: d-penicillamine

Pupillary fibers from the optic tract exit before reaching the lateral geniculate body (LGB)
and exit into the pretectal olivary nuclei.

Pseudotumor cerebri does not recur during pregnancy.

Craniopharyngioma is the most common cause of seesaw nystagmus.

Myelinated nerve fibres:
o
Myelinated fibres may represent a choristoma resulting from ectopic
oligodendrocytes.
o
About 1 % prevalence
o
More common in boys
o
Bilateral in 20%
o
An enlarged blind spot may be present with a peripapillary lesion, and peripheral
lesions may give corresponding field defects. Myopia and amblyopia may be
associated, and symptomatic macular involvement has been reported. Rarely,
associated retinal vascular abnormalities can be present.
o
Systemic associations include NF1 and Gorlin (basal cell naevus) syndrome.

Optic nerve pits are usually in the inferotemporal quadrant or central part of the disc.

Just Red-free photographs and VF are of no value in distinguishing pseudopapilledema
with buried drusen from true papilledema.
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Botulinum Toxin
o
Botox A
o
causes irreversible blockage of the pre-synaptic neurone and thus inhibits the
release of acetylcholine.
o
The onset of action is 72 hours, with a mean duration of action of 4 months.
o
Termination of action is the result of regeneration of new dendrites.
o
Muscle atrophy occurs in prolonged use of botulinum toxin.

Optic nerve drusen occurs in 2% of optic nerve specimens on histopathology and is
bilateral in 50%. Pathologic studies have revealed intra-axonal calcification of mitochondria.
The nerve head may be elevated, but no axonal swelling or edema exists. Optic nerve
drusen may be inherited in an autosomal dominant fashion and occur more frequently in
whites. Visual loss can occur and is thought to result from axonal compression, subretinal
hemorrhage, or choroidal neovascular membrane formation. Systemic conditions associated
with optic nerve drusen include Paget's disease, Ehlers-Danlos, sickle cell, and
pseudoxanthoma elasticum.

Foster Kennedy's syndrome: it is classically produced by a large subfrontal meningioma
which compresses one optic nerve (causing ipsilateral optic atrophy) and foramen of Monro
(causing hydrocephalus and contralateral papilloedema). Dr. Foster (first name) Kennedy
(last name) was a well-known American neurologist in the beginning of 20th century and
was once the president of the American Neurological Association.

3rd CN comes out in between posterior cerebellar and superior cerebellar arteries.

Palinopsia (or paliopsia) is the perseveration of a visual image in time.

Tuberculomas account for 40 % of space occupying intracranial masses. However isolated
brainstem tuberculomas are rare and account for only 5% of all intracranial tuberculomas in
endemic area.
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Premature baby has no pupillary light reaction until 3 weeks of gestational age

Ethambutol toxicity: up to 6% at a daily dose of 25 mg/kg and rare with a daily dose not
exceeding 15 mg/kg. Toxicity typically occurs within 3–6 months of starting treatment.

Demyelinating Optic neuropathy is caused by Amiodarone. It affects just over 1% of
patients during the initial 8 years of therapy and just under 2% during the subsequent 10
years.

Schilder disease, which is a very rare, relentlessly progressive, generalized disease with
an onset prior to the age of 10 years and death within 1–2 years. Bilateral optic neuritis
without subsequent improvement may occur.

Two important risk factors for fellow eye involvement in NAION are poor visual acuity in
the first eye and diabetes mellitus.

In GCA, the severity and extent of involvement are associated with the quantity of elastic
tissue in the media and adventitia. Intracranial arteries, which possess little elastic tissue,
are usually spared.

Chromophobe adenoma is the most common primary intracranial tumour to produce
neuro-ophthalmological features.

As the optic radiations pass posteriorly, fibres from corresponding retinal elements lie
progressively closer together. For this reason, incomplete hemianopia caused by lesions of
the posterior radiations are more congruous than those involving the anterior radiations.

Cogan dictum: If the lesion is in the occipital lobe, the smooth pursuit pathways are intact
and OKN will be symmetrical. If a homonymous hemianopia is due to a lesion in the parietal
lobe, the smooth pursuit pathways towards the side of the lesion are likely to be affected,
making this component of OKN defective.
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
An important sign of cavernous sinus lesions is sensory loss over the distribution of the first
division of the trigeminal nerve.

elephantiasis nervosa = Diffuse plexiform neurofibromas

Meige syndrome is a combination of blepharospasm and involvement of the lower facial
and neck muscles.

Brueghel syndrome is blephrospasm associated with severe mandibular and cervical
muscle involvement.

Even with a Complete Homonymous Hemianopia, visual acuity should still be 20/20..!! as
half a macula is still intact.

Thus the cuneus gyrus receives projections from the superior retina and the lingual gyrus
from the inferior retina.

NMO: Devics diaease
o
NMO, Aquaporin4 antibody
o
Severe visual loss to start with
o
No improvement in 3 days of IVMP
o
Normal MRI at onset
o
Spinal cord MRI showing 3 or more segment involvement
o
Absence of cortical demyelination in NMO in contrast to MS
o
CSF pleosytosis > 50 cells
o
Ask patients about urinary retention
o
Nausea, vomiting and hiccups
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Interferon-beta makes NMO worse in contrast to MS
Blind spot of mariotte
o
physiological blind spot, "blind point", or punctum caecum
o
The first documented observation of the phenomenon was in the 1660s by Edme
Mariotte in France. At the time it was generally thought that the point at which the
optic nerve entered the eye should actually be the most sensitive portion of the
retina; however, Mariotte's discovery disproved this theory.
o
It is not present in octopus eye.

Kestenbaum's number: Kestenbaum proposed a test that is loosely based on the Gunn
phenomenon, in which the patient fixes in the distance with one eye, while the other eye is
occluded by the palm of the hand. The examiner holds a handlight with fresh batteries 1 inch
from the uncovered eye for 5 seconds to allow the pupils to stabilize. The size of the
uncovered pupil is then measured with a pupil gauge to the nearest 0.25 mm. The size of
the opposite pupil is then measured in the same fashion, and the difference between the two
eyes is determined after correcting for any initial anisocoria. This result is called
―Kestenbaum's number.‖

Supranuclear Imbalance:
o
Nystagmus: always has slow phase
o
Saccadic ossilation: they are rapid.

PCA: Posterior cortical atrophy is visual variant of Alzheimer disease.

Saccadic eye movements in neurological lesions are reduced in velocity, while restrictive
defects manifest normal saccadic velocity with sudden halting of ocular movement.

Patients with tonic pupil may also sweat excessively, sometimes only on one side of the
body. The combination of these 3 symptoms – abnormal pupil size, loss of deep tendon
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reflexes, and excessive sweating – is usually called Ross‘s syndrome. Mx: Thoracic
sympathectomy

Any lesion anterior to the lateral geniculate body would cause the ganglion axon cells to
degenerate leading to optic atrophy.

A junctional scotoma is a unilateral central scotoma associated with a contralateral
superior temporal field defect. In a patient that comes in with poor vision in one eye, it is
very important to check the contralateral visual field for superior temporal field loss.
Inferonasal retina fibers cross in the chiasm, passing into the contralateral optic nerve
(Willebrand‘s knee). The contralateral optic nerve is compressed near the chiasm. These
patients have decreased visual acuity and a relative afferent visual defect.

Monocular defects are prechiasmal except that the far temporal visual field is seen only by
one eye. Watch this in an anterior occipital infarct, which can produce a monocular temporal
defect.

Patients with postchiasmal defects typically have normal visual acuity, normal pupils, and
a normal exam of the ocular fundus. Papilledema, however, may be seen in patients with
space-occupying lesions.

Optic nerve sheath decompression does not relieve the orbital congestion and would not be
effective in thyroid eye disease.

Alexia and agraphia can occur in dominant angular gyrus involvement.

D15 testing can help distinguish the usual red-green color blindness from tritan axis defects,
which are commonly found in dominant optic atrophy.

The inability to initiate voluntary saccades is known as ocular motor apraxia. The patient
with the congenital onset of this disorder is unable to initiate voluntary horizontal saccades,
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but can make normal vertical saccades. Acquired ocular motor apraxia usually occurs with
bilateral cerebral hemisphere disease. Patients with Parkinson's disease show difficulty in
initiating multiple repetitive saccades.

Oculoplasty


Valves in Lacrimal System
o
The valve of Rosenmüller is located between the common canaliculus (sinus of
Maier) and the lacrimal sac and prevents reflux back into the canalicular system.
o
The valve of Bochdalek is at proximal end of common canaliculus.
o
The valve of Krause (and sinus of Arlt) is located at the junction of the
nasolacrimal sac and duct.
o
The spiral valve of Hyrtle and the valve of Taillefer are located within the
nasolacrimal duct.
o
Valve of Hasner is at the end of NLD at opening in inferior meatus.
Enophthalmos
o
Metastatic schirrous breast carcinoma
o
Malignant syringomas (rare forms of sweat gland carcinoma of eyelid)
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Blow-out fracture

A rare variant of dermoid cyst, which has been termed a ―conjunctivoid‖ occasionally, is
found in the nasal orbit. These unusual dermoids are lined by conjunctival epithelium and
has goblet cells which are PAS positive.

Festoons: malar bags, seen in patients with thyroid orbitopathy

Kimura‘s disease is a rare inflammatory disorder of unknown cause, primarily seen in
young Asian males. The disease is characterized by a triad of painless subcutaneous
masses in the head or neck region, blood and tissue eosinophilia, and markedly elevated
serum immunoglobulin E levels.

Rosai-Dorfman disease: Sinus histiocytosis with massive lymphadenopathy. Large
histiocytes in orbital infiltrate have phagocytized lymphocytes, a process called
emperipolesis. The histiocytes are S-100 positive.

Algernon Reese 50-50 Rule of Lacrimal Gland Pathology

o
~50% of the lesions originate from epithelial elements of the lacrimal gland and 50%
are of nonepithelial origin.
o
Of nonepithelial lesions, 50% are lymphoid tumors and 50% are comprised of
various infections and inflammatory pseudotumors. (though now inflammatory are
more common 60-80%)
o
Among the epithelial tumors of the lacrimal gland, ~50% are pleomorphic
adenomas (benign mixed tumors) and 25% adenoid cystic carcinoma, while the
remaining tumors are composed of other types of carcinoma.
Rundle Curve: According to the Rundle's curve, Graves' ophthalmopathy (GO) worsens
during an initial phase up to a peak of maximum severity, to then improve and reach a
static plateau, with the activity curve preceding the severity curve by a few months.
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
Detection of mild pulsatile proptosis: Mild pulsation is best detected on the slit-lamp,
particularly during applanation tonometry.

The Zimmerman-McLean-Foster hypothesis:
o
In 1979, Zimmerman and colleagues proposed that enucleation of a globe with
choroidal melanoma may actually decrease survival, noting the rise in the
mortality rate in the years following enucleation from a baseline of 1% per year to a
peak of 8% per year during the second year following enucleation.
o
The rate subsequently returned to its baseline level of 1% per year over the next
3 to 5 years.
o
The authors suggested two possible explanations:
o



overwhelming tumor dissemination during surgery

lowering of the host‘s immunologic defense.
data from the COMS published in 1998 demonstrated that no survival advantage
was gained by pre-enucleation radiation in more than 1,000 patients with large
choroidal melanomas. This result suggests that metastasis occurs prior to
enucleation.
Choroidal melanoma
o
Mixed type is most common
o
Spindle A has best prognosis
o
Epithelioid has worst prognosis
Pseudoretraction is ruled out by elevating the other side eyelid (appearing ptotic) and
making that eye to fixate. In case of pseudoretraction the retracted appearing eyelid
assumes normal position once the contralateral eye is made to take up fixation.
Causes of pseudoretraction are: ptosis of the other eye, namely acquired apponeurotic
type, facial palsy of the same side causing unopposed action of the levator and hemifacial
spasm on the opposite side.
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
Floppy eyelid syndrome would have a papillary conjunctival reaction. Filaments are not
associated with this condition.

Although Marfan's disease is a disorder of collagen synthesis, blue sclera is not seen in this
condition?
(This is controversial! some reference says it is a cause of blue sclera and some says it is
not. I also found one MCQ which answers marfans as an exception of cause of blue sclera.
Oh Dear GOD!)

Dermoids are choristomas containing ectodermal elements (skin, hair, fat, and sebaceous
glands). Muscle tissue is not expected to be found in such a lesion.

Fraser Syndrome (cryptophthalmos-syndactyly syndrome): cryptophthalmos, renal
agenesis, laryngeal stenosis, syndactyly, aural and genital anomalies

Parry‘s sign: Exophthalmos in thyroid disease

Pseudo–von Graefe sign: Lid elevation on adduction or downgaze due to aberrant
regeneration of cranial nerve III.

von Graefe's sign: slow or restricted descent of the lid on attempted down gaze seen in
thyroid ophthalmopathy.

Limbal dermoids are usually an isolated abnormality but may on occasion be part of
Goldenhar's syndrome, Treacher Collins' syndrome or the naevus sebaceous
syndrome of Jadassohn.

Very rarely, capillary haemangioma is part of a wider syndrome Maffucci's (multiple
systemic haemangiomata and bone lesions) or Kasabach-Merritt (haematological
abnormalities).
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
JACOB‘s ulcer: BCC or rodent ulcer of an eyelid.

Multiple endocrine neoplasia, type IIb (Sipple-Gorlin syndrome), is associated with
enlarged corneal nerves, not type 1.

Phthirus pubis (crab louse) infests pubic hair and eyelashes and is transmitted by sexual
contact. Treatment is by mechanical removal or with bland ointments applied to the lids to
suffocate adult lice. Physostigmine is effective as a respiratory poison against the lice but
has many ocular side effects, limiting its effectiveness.
Demodex is a normal commensal in adults living in meibomian glands. Classically,
―sleeves‖ are found at the base of lashes, indicating Demodex infestation. Treatment is
through lid scrubs. Collarettes are found more commonly with staphylococcal blepharitis.

Conjunctival lymphoma: painless, salmon-colored lesion on the bulbar conjunctiva.

Mucoepidermoid carcinoma: aggressive variant of squamous cell carcinoma. It should
be suspected in cases involving recurrence after primary excision or in which no invasion
into the globe occurs. It typically occurs in patients over age 60 and involves cells that are
able to produce malignant mucussecreting cells (goblet cells).

Basal cell carcinoma is the most common malignant tumor of the eyelid skin, but
squamous cell carcinoma is the most frequently occurring malignancy of the conjunctiva.
Squamous papillomas are benign lesions that can, on rare occasions, undergo malignant
transformation.

Conjunctival malignant melanoma: pigmented elevated lesion, enlarges progressively
with time. It occurs most commonly on the bulbar conjunctiva. These tumors are very
vascular, and dilated vessels may be seen feeding the tumor. The prognosis is generally
better than cutaneous melanomas. A systemic metastatic work-up is necessary to direct
treatment. Conjunctival melanomas can arise de novo (30%), from nevi (40%), or from
primary acquired melanosis (30%).
A conjunctival nevus: flat or slightly elevated pigmented lesion of the bulbar conjunctiva.
It may have epithelial inclusion cysts within its substance. These lesions can grow or
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enlarge during adolescence or with pregnancy. Suspicious lesions should be biopsied to
rule out melanoma.
Primary acquired melanosis (PAM): unilateral condition found in middle-aged white
people. These multiple, superficial, flat patches of pigmentation develop into malignant
melanoma in 20% to 30% of these patients. Excisional biopsy should be performed on any
suspicious nodular lesions.
Racial or ocular melanosis: most commonly in pigmented individuals and represents
benign collections of melanin in the conjunctiva. It appears as a perilimbal dusting of
light brown pigment. No malignant potential exists.

Congenital NLDO:
o
It is estimated that congenital nasolacrimal duct obstruction occurs in 73% of
newborns but only 6% are symptomatic.
o
The most common site of obstruction is at the valve of Hasner.
o
In a dacryocystocele, there is concurrent obstruction in the common
canaliculus - therefore, compression of the sac does not show reflux.
o
A mucocele increases the risk of orbital cellulitis and early probing is
recommended. The success of first probing in congenital nasolacrimal duct
obstruction approaches 90%.
o
Probing for congenital NLDO should not be done before 9 months??
o
In dacryocystocele, early NLD probing is required.

Synophrys is extension of the eyebrows to the midline. It can occur in naturally hairy
individuals who are otherwise normal. It also occurs in Cornelia de Lange syndrome which is
characterized by mental retardation, limb reduction, flared nostrils, and hirsutism.

Involutional ptosis should not be confused with myasthenic ptosis because it
frequently worsens towards the end of the day. This is because of fatigue of Müller muscle,
which has to work harder to keep the lid elevated.

After permanent punctal occlusion with cautery, 20-30% rate of recanalization is expected.
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potential ocular complications associated with nevus of Ito & nevus of Ota:
a. Open-angle glaucoma.
b. Malignant melanoma.

Squamous cell carcinoma is the most common malignant tumour of the conjunctiva and
typically affects the limbus. It typically occurs in people over the age of 50. Because of its
limbal location, it may sometimes be misdiagnosed as pterygium or pingueculae.

SCC is rare amongst healthy young people, its occurrence in patients under the age of 50
should raise the possibilities of AIDS. In African countries where AIDS is endemic, SCC
conjunctiva is now recognized as an AIDS defining disease.

Basal cell carcinoma that involves the medial canthus is the most likely to invade the deep
orbital structure.

Recently, intralesional injection of OK-432 (group A Streptococcus pyogenes of human
origin which is used as an anticancer agent) has been reported to shrink orbital
lymphangioma.

Axis of optic canal make 36 degree angle with the midline.

Melanoma with best prognosis: Iris. (can be excised completely)
If isolated to the iris, malignant melanoma behaves in a more benign fashion than does
melanoma of the choroid. Involvement of the ciliary body or choroid portends a poorer
prognosis. Metastases are rare, and localized iridectomy may remove the tumor entirely.
These lesions may be pigmented or amelanotic. Ipsilateral hyperchromia may be present.
Iris melanoma has spindle B cells(?)

Epiphora is watering due to lacrimal outflow abormality.
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
Complications of chronic dacryocystitis are all except entropion.

Everbusch operation for Ptosis: Skin side
Dhaval Patel MD
Blascovisc operation for Ptosis: Conjunctiva Side

ROPLAS: Regurgitaion over pressure on lacrimal sac

Entropion does not have any subtype like paralytic entropion.??

Congenital acquired fistula: probe test positive, both opening probe touch…why to
differentiate?  as it does not close its own.. whereas acquired one closes once u treat the
cause.

Sac dilatation: atonicity, long term

Quikert suture: entropion and ectropion: place knot where u want lid to be.If entropion, at
margin and vice versa.

RB patients will least likely to have low IOP, microphthalmos, Cataract.

Iris Nevus and Melanoma:
o
An iris nevus can be distinguished from a melanoma by: size (<3 mm in diameter),
thickness (<1 mm thick), and the absence of vascularity, ectropion uveae,
secondary cataract, secondary glaucoma, and growth.
o
Iris fluorescein angiogram (a nevus has a filigree filling pattern that becomes
hyperfluorescent early and leaks late or is angiographically silent, whereas a
malignant melanoma has irregular vessels that fill late), and B-scan ultrasound or
UBM to rule out ciliary body involvement. Transillumination may also be helpful.
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Dhaval Patel MD
Cornelia de Lange's syndrome:
o
dysmorphic features are characterized by bushy eyebrows, long curly eyelashes,
hirsutism, long philtrum, thin upper lip and down turned angles of the mouth. Late
eruption of widely spaced teeth. Limb anomalies are common and consisted of
micromelia, phacomelia and oligodactyly. There are growth and mental retardations.
o
chromosome 13q deletion syndrome
Patients with extensive haemangiomas may have:
(1) Kasabach–Merritt syndrome, which is characterised by thrombocytopenia, anaemia
and low levels of coagulant factors;
(2) Maffucci syndrome, which is characterised by enchondromata of hands, feet and long
bones as well as bowing of long bones;
(3) high-output heart failure.

The orbit is pear-shaped. Its widest dimension approximately 1 cm posterior to the anterior
rim.

Blunt cranial trauma is often transmitted to the sphenoid, with secondary indirect
traumatic optic neuropathy as a consequence.

In hypertelorism, the medial orbital walls are separated excessively. In exorbitism, the
lateral walls diverge excessively (>90 degrees).

The most frequent cause of bilateral proptosis in adults is thyroid ophthalmopathy. The
most common cause of bilateral proptosis in children is not definitively established, but
metastatic neuroblastoma and/or leukemia should be considered.
The most common cause of unilateral proptosis in adults is thyroid ophthalmopathy.
The most common cause of unilateral proptosis in children is orbital cellulitis.
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
Although computed tomography (CT) scan does use greater radiation than plain films, it
involves less than plain film tomography, which requires multiple exposures. An orbital CT
scan administers a dose of 1 to 2 centigrays per scan.

Long T1 times render a substance hypointense (dark) on magnetic resonance images
(MRI).
Orbital fat behaves opposite to vitreous. To determine the type of magnetic
resonance imaging (MRI), look for which is brighter. If the fat is brighter, it is a T1weighted image. If the vitreous is brighter, it is a T2-weighted image.

A bluish bulge above the medial canthal tendon (MCT) is typically a meningocele, whereas
one below is typically a dacryocele.

most common risk factor for the development of preseptal cellulitis- recent skin trauma
most common risk factor for the development of orbital cellulitis- ethmoid sinusitis

First-generation cephalosporins (e.g., cefazolin, cephalexin, cephalothin) are only
effective against half of the isolates of Haemophilus influenzae, and are generally
insufficient to cover anaerobes. Second-generation agents (cefuroxime) are preferred.
Also note that third-generation cephalosporins (e.g., cefotaxime) have less activity than
first-generation cephalosporins against Gram-positive organisms, especially Staphyloccocus
aureus.

Orbital studies are incomplete without coronal sections (preferably nonreconstructed, which
requires the patient to lie prone).

Hamartomas are abnormal tissue in a normal place (think of ―hammer home‖);
choristomas are comprised of normal tissue in an abnormal location.

Capillary hemangiomata will blanch with pressure, whereas the nevus flammeus does not.
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
Mucor, Rhizopus, and Aspergillus can lead to necrotizing orbital cellulitis.

The atrophy of myofibrils is felt to be secondary to compression by surrounding edema. The
latter occurs with deposition of glycosaminoglycans in the presence of inflammatory cell and
fibroblast infiltration. Antibodies to the thyroid-stimulating hormone (TSH)-receptor
expressed on fibroblasts may make them target cells for the inflammation observed
in Graves' ophthalmopathy. Primary destruction of myocytes does not seem to occur.

The fragile pial vessels supplying the optic nerve are easily disrupted by any attempt to
remove optic nerve meningoma. Surgery is usually undertaken if there is intracranial
extension or severe proptosis and severe visual loss.

what percentage of lacrimal gland lesions will be inflammatory/lymphoid?
general ophthalmologist's practice: 10%
orbit specialists: 50%

Fibrous dysplasia may be monostotic (affect only one bone) or polyostotic. The
polyostotic variety may present with precocious puberty and dermal hyperpigmented
macules. This disorder, Albright's syndrome, rarely involves the orbit. Orbital disease is
nearly always monostotic and rarely associated with precocious puberty, regardless of age.
Surgical curettage or excision is usually undertaken. Only woven bone, not cancellous, is
found microscopically.

Eosinophilic granuloma frequently involves the orbital bones. The classic triad of HandSchüller-Christian disease consists of proptosis, lytic skull lesions, and diabetes
insipidus. Orbital involvement is rare in Letterer-Siwe disease.

It is impossible to differentiate clinically or radiologically between benign reactive lymphoid
hyperplasia and orbital lymphoma. Biopsy with light microscopy, immunochemical
staining, and electron microscopy is necessary to distinguish between them.
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
The central nervous system (CNS) is not routinely surveyed in patients with orbital
lymphoma. This is in contrast to patients with intraocular lymphoma.

Both orbital inflammatory syndrome and lymphoproliferation are composed of
polyclonal lymphocytes (although lymphoma contains a monoclonal subpopulation). Cellular
heterogeneity is a feature of both orbital inflammatory syndrome and reactive lymphoid
hyperplasia. The key features separating the two are (i) prominent fibrovascular stroma
and (ii) hypocellularity, both seen in pseudotumor and not in lymphoid activation.

The three orbital deposits that are hyperintense on T1-weighted images are blood,
melanin, and mucous. (Fat..?)

The tripod complex is produced by three distinct fractures along suture lines—
zygomaticofrontal, zygomaticomaxillary, and the zygomatic arch. Ocular motility may or
may not be normal in pure tripod fractures, but upgaze should be spared. Repair is indicated
when there is marked cosmetic deformity or potential mandibular instability.

Telecanthus and rounding of the medial canthus are characteristic findings in direct
naso-orbital-ethmoid fractures.

The deep head of the pretarsal muscle (Horner's tensor tarsi) is a localized bundle of
pretarsal orbicularis that is critical to adequate tear drainage. It surrounds the lacrimal sac
and, with each blink, pumps tears downward into the nasolacrimal duct.

The lacrimal sac fossa is formed by the frontal process of the maxilla and the lacrimal
bone. It cradles the lacrimal sac and is continuous with the nasolacrimal canal.
The lacrimal gland fossa lies in the anterolateral orbital roof within the zygomatic process
of the frontal bone.

nodules with central craters: keratoacanthoma & molluscum contagiosum 
keratoacanthoma shows more inflammation
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
The syringoma is derived from sweat gland tissue.

An alternate name for pilomatrixoma is the ―calcifying epithelioma of Malherbe.‖

Ephelis: increased melanin content of normal (or decreased) numbers of melanocytes.
Lentigo: increased number of melanocytes
Nevi: Melanocytes in nevi are referred to as ―nevus cells‖ to reflect this difference. Nevus
cells are rounder, with distinct margins and more abundant, eosinophilic cytoplasm.

sebaceous cell carcinoma: not a/w chronic sun exposure

Cogan‘s sign: Upper eyelid twitch when patient with ptosis refixates from downgaze to
primary position; nonspecific finding in myasthenia gravis; also refers to venous
engorgement over lateral rectus muscle in thyroid disease

plexiform neurofibroma of the upper eyelid: bag of worms.

Epibulbar dermoids are solid choristomas. Adnexal dermoids are generally cystic.

BHID: benign hereditary intraepithelial dyskeratosis: Oral mucosal leukoplakic lesions,
bilateral bulbar leukoplakia  obscure, dominantly inherited condition found in a very few
number of North Carolinians.

Noninvasive way to reduce Lid Retraction temporarily
o
2.5% topical phenylephrine to increase the palpebral aperture of the contralateral
eyelid to reduce the differences
o
chin can be lowered
o
sitting position with her eyes looking up
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congenital skin crease asymmetry:
o
The eye that does not have the skin crease appears smaller because the upper
eyelid skin forms a hood over the lid margin
o
The height of the skin crease is due to the interplay of several structures: the level of
the orbital septum, the amount of subcutaneous fat and the level of insertion of the
levator aponeurosis to the skin. In the East Asians (mainly Chinese, Koreans and
Japanese), the skin crease is lower or absent in comparison with other races for the
following anatomical reasons:
o
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Dhaval Patel MD

the fusion of the orbital septum to the levator aponeurosis is lower (usually
below the superior tarsal border);

the presence of a thick subcutaneous fat layer and preaponeurotic fat
protrusion prevent the levator fibres from inserting into the skin near the
superior tarsal border;

the primary insertion of the levator aponeurosis into the orbicularis muscle
and the eyelid skin occurs closer to the eyelid in the East Asians.
To achieve eyelid symmetry, the best way is to create a symmetrical skin crease in
the eye without one. This may be achieved by two means:

Surgical method: The skin crease may be created by excising a strip of skin
+/- orbicularis oculi or by the buried suture method.

Non-surgical method: The skin crease may be formed using sticker or glue.
This may be or by other cosmetic means (sticker or glue).
The most common vascular lesions of the orbit
o
Cavernous haemangioma typically present in patient over the age of 30 and the
lesion tends to be intraconal. Blood fluid level is uncommon.
o
Capillary haemangioma usually becomes appear ant at birth or within the first 8
weeks of birth. The lesion typically gives a red cutaneous appearance.
o
Orbital varix shows positional proptosis and typically involves the superior
ophthalmic vein.
o
Lymphangioma most commonly presents in patient under the age of 10. On CT or
MRI scan the lesion is usually extraconal but may show intraconal extension. The
lesion has ill-defined edges but with time partial encapsulation may occur due to the
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attempt of the body to form barrier to limit its growth. Bleeding into cystic spaces
gives a blood-fluid level.
Clinically, lymphangioma causes a slowly progressive proptosis with globe
displacement, ptosis, and restrictive eye movement. The eyelid may have a bluish
discoloration from subcutaneous involvement. Sudden worsening of the proptosis
may be caused by bleeding into the cystic spaces. Enlargement of the lesion
following upper respiratory tract infection is a characteristic feature; this is caused by
lymphoid reaction in response to infection. Macroscopically, the lesion usually
appears dark red with cystic spaces which may contain dark blood. Histologically,
the lesion is made up of bloodless ectatic lymph channels and contain spaces lined
by a single layer of flat mesothelial cells.

In Conjunctival lymphoma, If the histology shows a reactive lymphocytic hyperplasia
(B-cell type) and within the classification of pseudo B- tumor, then systemic involvement is
unlikely.
If there is associated Proptosis, then DD should be Systemic lymphoma-with orbital
involvement, B-cell replication most common of a rare condition; leukaemias with orbital
involvement are a more common association; pseudo-tumours and lacrimal tumours.

Boston‘s sign: Lid lag on downgaze in thyroid disease

Enroth‘s sign: Eyelid edema in thyroid disease

Prognosis for histiocytosis is poor in Children with disease onset younger than 2 years
with multifocal disease (especially those with compromised liver or lung function, or impaired
hematopoiesis).

The distinction between fibrous dysplasia and ossifying fibroma is generally made
histologically. If osteoblasts are present, then the lesion is called an ossifying fibroma;
if absent, the term fibrous dysplasia is applied.

Blood stagnation and phleboliths are characteristic of cavernous, not capillary,
hemangiomas.
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
pathology of the nevus flammeus (port-wine stain): dilated capillaries without the
endothelial cell proliferation which accounts for their flat clinical appearance.

proptosis with the Valsalva maneuver: orbital lymphangioma, capillary hemangioma,
orbital varix. NOT IN Orbital CAVERNOUS Hemangioma

Rhabdomyosarcoma
o
Pleomorphic or well-Differentiated rhabdomyosarcoma is the least common type
but has the best prognosis.
o
The embryonal type is the most common.
o
The alveolar type has the worst prognosis.
o
Rhabdomyosarcoma originates from undifferentiated pluripotential
mesenchymal cells in the orbit. The tumor does not arise from malignant
transformation of extraocular muscle (EOM).
o
The cell of origin is presumably an undifferentiated, pluripotent cell of the soft tissue.
These cells have the capacity to differentiate toward muscle with production of
myosin and actin and to show cross-striations.
o
Immunohistochemistry shows positivity for vimentin, myosin, myoglobin, musclespecific actin, and desmin.
o
Children with rhabdomyosarcoma present with rapidly progressive unilateral,
painless proptosis. Swelling and ecchymosis may resemble orbital cellulitis.

Plexiform neurofibroma is most specific for neurofibromatosis. Unlike schwannomas,
neurofibromas grow independent of peripheral nerves. In addition, they are generally
osteolytic. The association of neurofibroma with congenital glaucoma is strongest with
lesions of the upper eyelid.

Positive staining for S-100 is characteristic of any cell derived from the neural crest.

Drugs causing myasthenia or exacerbating the condition are: penicillamine,
aminoglycosides, quinidine and propranolol
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
Most important two tests in pre-surgical work-up of PTOSIS are corneal sensations and
bell‘s phenomenon, as if abnormal, they are contraindications to surgery.

Two common surgical procedures for senile entropion will be: Bick procedure modified by
Reeh and Jones, Reeh and Wobig procedure.

The distance between the lateral orbital rim and the anterior corneal surface is measured
while doing exophthalmometry. The corneal reflex that is seen in the mirror of the
exophthalmometly is then taken as the reading.

Naugle exophthalmometer uses the upper and lower orbital rims for fixation of the
instrument

Lesion of actinic keratosis is premalignant whereas those of seborrhic keratosis are
not.

In involutional ptosis, there is dehiscence of the levator aponeurosis resulting in an
elevated skin crease. The ptosis is constant in up- or down-gaze. The up-gaze is not
affected as in some congenital ptosis. Levator advancement is the treatment of choice.

DCR involves removing most of the lacrimal bone.

Naso-orbito-ethmoidal fracture has been discovered as the main cause of traumatic
NLDO.

Orbital emphysema usually results from medial wall fractures (not floor fracture..!!) such
that sneezing or nose-blowing forces air from the paranasal sinuses into the orbital tissue.
Prophylactic antibiotic prevents orbital cell ulitis. The fracture is often small and difficult to
locate even with a CT scan. The majority of cases resolve spontaneously and surgery is
rarely required.
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Dhaval Patel MD
The Ellebogens' criteria for the ideal eyebrow position and contour are:
o
the brow ends laterally at an oblique line extending from the ipsilateral alar base and
ipsilateral medial canthus
o
the brow ends laterally at an oblique line extending through the ipsilateral alar base
and lateral canthus
o
the medial and lateral ends of the eyebrow lie at about the same horizontal level
o
the apex of the brow lies directly above the lateral limbus of the eye
o
the brow arches above the supraorbital rim in women and lies about at the level of
the rim in men
Zimmerman‘s tumor: Phakomatous choristoma
o
Lower nasal eyelid or anterior orbital tumor of infants, probably congenital
o
A choristoma of lenticular anlage composed of cells resembling lens
o
epithelium surrounded by thick PAS + lens capsule-like basement membrane,
expresses lens proteins
o
The epithelial cells of the phakomatous choristoma stained positively for S-100
protein and vimentin, the intermediate filament normally found in lens epithelial cells.
Keratin markers were negative.

Steroid Injection for Chalazion: A steroid injection can lead to permanent depigmentation
or atrophy of the skin at the injection site. The manufacturer of triamcinolone has recently
recommended against its use intraocularly and in the periocular region. Vigorous injection
can rarely result in retrograde intraarterial injection with resultant central retinal artery
occlusion. Use of triamcinolone injection for chalazion treatment must include a detailed
discussion between physician and patient, as well as adequate documentation in the
patient's record.

Papilloma is benign eyelid tumor but remember that it is not caused by human papilloma
virus.
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
Conjunctival amyloidosis is typically composed of immunoglobulin light chains but patients
usually do not have systemic disease.

Conjunctival melanoma arises 75% from PAM, 26% mortality and they metastatise to
regional noded unlike uveal melanoma which metastatise to liver.

Oncocytoma of cauncle arises from accessory lacrimal glands of popoff.
o
Also known as adenolymphomatous tumor, apocrine cystadenoma, oxyphilic cell
adenoma
o
rare, mostly benign neoplasms and are mostly found on the caruncle.
o
This tumor arises from accessory lacrimal glands in the caruncle, especially in
elderly women. It also can arise from accessory lacrimal glands.
o
Histologic examination reveals solid nests and cords of polyhedral cells exhibiting
abundant, finely granular acidophilic cytoplasm and round to oval paracentral nuclei,
usually containing a single prominent nucleolus. Cystic cavities are identified within
the tumor.
o
Electron microscopic examination shows a cytoplasm densely packed with
mitochondria. The mitochondria are sometimes atypical. This is characteristic of
oncocytomas.

Mesotherapy: In this technique drugs or nutrients are injected in the skin and subcutaneous
tissue to obtain a therapeutic effect. This modality of therapy has not yet received FDA
approval.

Chemical Peeling agents: Alfahydroxy acid peel, Trichloracetic acid peel, Phenol peel.

Fillers:
Temporary fillers are- Zyderm and Zyplast, Cosmodum and Cosmoplast, Hyaluronic
acid gel, Restylane, Radiance FN, Revidum intra, Cymetra sculptra
Permanent fillers are- Artecoll- PMMA microspheres in 3.5% collagen. Sheba –
Injectable microionised humandermis.
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Botulinum toxin A
o nature‘s strongest blocker of nerve impulses
o apporoved by FDA for use in blepharospasm, strabismus and hemifacial spasm
o stored at -5 degree celsius and is available in 50-100 unit vials.
o reconstituted with 0.9% sodium chloride and should be ideally used in 4hrs and
stored at 2-8 degree

Mille‘s Syndrome: facial nevus flammeus and angioma of the choroid in absence og
glaucoma.

‗panda eyes‘: always suspect skull base fracture

Centurion syndrome is characterized by anterior malposition of the medial part of the lid,
with displacement of puncta out of the lacus lacrimalis due to a prominent nasal bridge.

Sump syndrome complication of DCR, in which the surgical opening in the lacrimal bone is
too small and too high. There is thus a dilated lacrimal sac lateral to and below the level of
the inferior margin of the ostium, in which secretions collect, unable to gain access to the
ostium and thence the nasal cavity.

Giant fornix syndrome: This is due to retained debris in the upper fornix that is colonized
by S. aureus, usually in elderly patients with levator disinsertion. Secondary corneal
vascularization and lacrimal obstruction are common. Treatment involves thorough cleaning
of the fornix, and topical and systemic antibiotics.

The brow fat-pad continues into the upper lid as filmy areolar tissue found posterior to the
orbital and preseptal orbicularis muscle, termed the retro-orbicularis oculi fat (ROOF),
located within the superficial musculoaponeurotic system (SMAS).
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
In lower lid, deeper suborbicularis oculi fat (SOOF), less substantial than the malar fat,
extends over the body of the zygoma and is continuous inferiorly with the fat deep to the
zygomatic major and minor muscles. The suborbicularis oculi fat is located deep to the
SMAS and may also droop with aging. In cases of paralytic ectropion from Bell's palsy,
ptosis of the suborbicularis oculi fat may need to be addressed in the surgical management.

Lymphoedema–distichiasis syndrome: AD with high penetrance but variable expressivity.
Congenital distichiasis along with primary lymphoedema of the legs.

Summerskill sign: eyelid retraction in uremia

In retinoblastoma aqueous to serum LDH ratio is >1, phosphoglucose to isomerase ratio
should be >2.

Molluscum contagiosum: large poxvirus
o
Syndrome associated are weskott-aldrich syndrome and AIDS

PIEZOMETRY: orbitometry

Hypotelorism is seen in patau syndrome.

Iliff's sign: This involves everting the eyelid and asking the patient to look up. Failure of the
eyelid return to its normal position when the patient looks up indicates poor LPS muscle
function.

The ETA as described by Baylis is an accurate technique for ptosis correction in patients
with poor EPMs.
o
External Tarsal Aponeurectomy ETA
o
millimeter for millimeter correction of ptosis
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o
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Dhaval Patel MD
not only elevates the upper eyelid but also provides a spacer or graft for the lower
eyelid
dictyoma
o
A benign tumor of the ciliary epithelium with a netlike structure resembling
embryonic retina.
o
aka medulloepithelioma
o
Nonteratoid and teratoid varieties (presence of heteroplastic elements) are known.
Both can be benign or malignant.
o
The teratoid type may contain cartilage and/or rhabdomyoblasts.

Cicatricial entropion is seen in  trachoma, due to cicatritial contraction of conjunctiva.

Removal of the palpebral part of lacrimal gland leads to the gland becoming non-secreting.

The Neosynephrine test is an evaluation of the effect of Muller‘s muscle contraction on the
degree of ptosis. One drop of 2.5% phenylephrine is placed in the eye. After 5 minutes, the
degree of ptosis is reevaluated. The phenylephrine causes contraction of the sympathetic
Horner‘s muscle, sometimes causing dramatic improvement in the degree of ptosis. If
phenylephrine corrects the ptosis completely, many surgeons elect to perform a Muller‘s
muscle resection as opposed to a levator resection.

Whitnall's orbital tubercle is located entirely on the zygomatic bone approximately 2 mm
inferior to the frontozygomatic suture line.

Rosengren-Doane‘s Lacrimal Pump Mechanism:
o
Contraction of the orbicularis muscle provides a positive pressure in the tear sac,
forcing tears into the nose through the valve of Hasner.
o
Once the eyelids open and move laterally, a negative pressure is produced in the
tear sac, which is maintained by the valve of Hasner.
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
The lacrimal sac fossa is bordered by the anterior lacrimal crest of the maxillary bone and
the posterior lacrimal crest of the lacrimal bone. In a dacryocystorhinostomy (DCR), the
ostomy is created at the maxillolacrimal suture line located in the lacrimal sac fossa.

Pseudostratified columnar epithelium lines the nasolacrimal sac, duct, and canaliculi.

The slight indentation or groove in the central aspect of the eyelid margin is the sulcus
intermarginalis of Graefe or the gray line which corresponds to the lid's orbicularis muscle
layer, the muscle of Riolan. It is not the mucocutaneous junction of the eyelid margin. The
mucocutaneous junction occurs posterior to the eyelashes near the opening of the
meibomian glands.

The Reese-Ellsworth classification was developed in the 1950s as a guide for predicting
visual prognosis in eyes treated by methods other than enucleation. It has been used
erroneously to predict patient prognosis for life.

The capillary hemangiomas are characteristically high flow lesions, in contrast to cavernous
hemangiomas, which are hemodynamically low flow.

Erdheim-Chester disease is a multisystem disease with lipogranuloma formation in the
liver, heart, kidneys, and bones. Histologically, these lipogranulomas contain histiocytes,
Touton giant cells, lymphocytes, and plasma cells. Ophthalmic manifestations of this
disease can include proptosis and xanthelasma-like skin lesions

Euryblepharon is a horizontal widening of the palpebral fissure.
Epiblepharon is commonly seen in Asian children and is caused by altered lower eyelid
retractor (aponeurosis) attachments, which allow overriding of the pretarsal orbicularis
above the eyelid margin. The result is posterior misdirection of the lower eyelashes and
potential keratopathy.
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Blepharochalasis is a rare inherited condition that occurs more commonly in young
females than in males and consists of repeated bouts of eyelid inflammation and edema.
Recurrent idiopathic eyelid swelling eventually leads to blepharoptosis secondary to
dehiscence or attenuation of the levator aponeurosis. Anterior bulging of the lacrimal gland
or orbital fat may also occur.
Dermatochalasis refers to the excess eyelid skin that occurs with aging.
Steatoblepharon refers to the bulging of orbital fat that also commonly occurs with aging or
attenuation of the orbital septum.
Blepharospasm may be associated with blepharoptosis and entropion caused by
aponeurotic dehiscence.
Dermatochalasis, steatoblepharon, and blepharospasm typically are not associated with
repeated bouts of eyelid edema and inflammation.

A retroblepharoplasty (transconjunctival blepharoplasty) or blepharoplasty via the
transconjunctival approach is used in lower eyelid blepharoplasty, NOT upper eyelid
blepharoplasty.

The two most common causes of DCR failure are obstruction at the common canaliculus
and obstruction at the bony ostomy site.

Studies have demonstrated that in up to 50% of patients tested, creation of a
monocanalicular state resulted in symptomatic epiphora. So upper or lower, canalicular
repair should be done leaving open the possibility of future trauma and disease to the
remaining canaliculus, and considering present surgical techniques with a high success rate
of repair, many recommend attempted repair of all recent canalicular lacerations.

Pneumococci are the most common organism causing acute dacryocystitis. Other
organisms include streptococci, diphtheroids, Klebsiella pneumonia, Haemophilus
influenzae, Pseudomonas aeruginosa, and mixed organisms. Actinomyces and fungi, such
as Candida, are also frequently seen.

Although Actinomyces israelii is associated most frequently with acute canaliculitis,
multiple organisms have been shown to cause this disorder. Streptomyces, Arachnia
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propionica (previously Streptothrix), Nocardia, and fungi, such as Candida albicans and
Aspergillus niger, have been documented to cause canaliculitis.

Chronic dacryoadenitis: nocardia

Nocardia is acid fast, actinomyces is non acid fast.

Of patients with mucormycosis, 70% have diabetes mellitus, 5% have renal disease, 18%
have other immunosuppressed states, 3% have leukemia, and only 4% have no systemic
illness.

The clinical signs of thyroid-related orbitopathy can be generally grouped into two
independent manifestations: type 1 and type 2 orbitopathy.
Type 1 orbitopathy comprises symmetric proptosis with symmetric eyelid retraction,
minimal orbital inflammation, and minimal extraocular muscle inflammation or restrictive
myopathy.
Type 2 orbitopathy comprises extraocular muscle myositis, restrictive myopathy, orbital
inflammation, and chemosis. Compressive optic neuropathy is more commonly a feature of
type 2 orbitopathy.

Fuchs' adenoma:
o
Fuchs' reactive hyperplasia, coronal adenoma, Fuchs' epithelioma, benign ciliary
epithelioma
o
proliferative rather than neoplastic
o
The lesion is composed of basement membrane material (type IV collagen and
laminin), acid mucopolysaccharides, glycoproteins, and proliferating cells of the
nonpigmented ciliary body epithelium.
o
It rarely may cause localized occlusion of the chamber angle.
o
A metastatic lesion from a malignant melanoma would display mostly pleomorphic,
pigmented cells with malignant features (high nuclear-cytoplasmic ratio, nucleoli, and
mitotic figures).
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Homer-Wright rosettes are characterized by cells that line up around an area containing
cobweb-like material, but no acid mucopolysaccharides are present. These rosettes are
not specific for retinoblastoma and are found also in neuroblastoma and
medulloepithelioma. Rhabdomyosarcoma displays no rosette formation.
In contrast, Flexner-Wintersteiner rosettes are the characteristic rosettes of
retinoblastoma but are not always present. The presence of Flexner Wintersteiner rosettes
makes the diagnosis of a well-differentiated retinoblastoma. In Flexner-Wintersteiner
rosettes, the cells line up around an apparently empty central lumen. However, special
stains show hyaluronidase-resistant acid mucopolysaccharides in the lumen.


Malignant Melanoma Eyelid Skin
o
all are rare representing less than 1% of eyelid tumors.
o
Superficial spreading melanoma accounts for 80% of cases. Superficial spreading
melanoma occurs both in sun-exposed and in nonexposed areas.
o
lentigo maligna and nodular melanoma each occur in 10% of cases. Lentigo maligna,
also known as melanotic freckle of Hutchinson, is sun induced.
o
Both have a long horizontal growth phase before invading the deeper tissues.
o
Nodular melanoma is more aggressive with earlier vertical invasion and has worst
prognosis.
Fibrous histiocytoma
o
slightly more common in men
o
Most are benign (>90%), and have a storiform, or matlike, pattern on histopathology.
o
Most common mesenchymal tumor of orbit in adults
o
It is usually very firm and can displace other orbital structures.
o
Ten percent have metastatic potential. Another 16% are termed ―locally aggressive‖
but not frankly malignant.
o
CD 34 positive on IHC, vimentin +, S100 -
o
Most common site is superonasal orbit
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
Pagetoid spread: Sebaceous cell carcinoma and PAM

Papilloma is treated with interferon alpha 2b. in recurrent cases oral cimetidine can be used.

Capillary hemangioma in PHACE syndrome:

o
Caution while using Propanolol
o
Due to Increased stroke risk
IgG4-Associated Orbital Inflammatory Disease
o
first recognized by the Japanese in 2001 in autoimmune pancreatitis (AIP)
o
number of diseases have now been recognized as part of the spectrum of IgG4-RD,
and these include sclerosing cholangitis, Mickulicz disease, Küttner tumor
(sclerosing sialadenitis), Riedel thyroiditis, multifocal fibrosis, Ormond disease
(idiopathic retroperitoneal fibrosis), and others
o
evidence of a role for Helicobacter pylori
o
Several recognizable patterns of orbital disease may occur with IgG4-ROD
o

Dacryoadenitis,

Dacryoadenitis (bilateral) with enlarged parotid and submandibular glands
(previously called Mickulicz disease

Orbital myositis

Sclerosing orbital disease
Treatment

empirical use of corticosteroids

methotrexate, mycophenolate, and cyclophosphamide.

rituximab.
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Community Ophthalmology


WHO declared the year 1976 as "The Year of Prevention of Blindness" and stated that
the 6 main causes of blindness were:
o
Cataract
o
Trachoma
o
Xerophthahnia
o
Onchocerciasis
o
Glaucoma and
o
Trauma
Severe visual loss is defined as a vision of 20/200 or worse.
Profound visual loss is defined as visual acuity worse than 20/400.
The World Health Organization (WHO) defines blindness as vision worse than 20/400.
The World Health Organization (WHO) defines low vision as vision worse than 20/60.
Eyes with severe visual loss (20/200 or worse) are considered legally blind in the United
States.

In 1948, the first randomized clinical trial (RCT) was published on the use of
streptomycin in pulmonary tuberculosis.

The Consolidated Standards of Reporting Trials (CONSORT) statement, which is
ascribed to by leading peer-reviewed journals, sets a high standard of quality in the
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reporting of randomized clinical trials (RCTs) in order to allow the reader to adequately
judge the quality of the study.

Average visual acuity is significantly better than 20/20 in individuals younger than 60
years.

Worldwide, more adults than children are blind.

Pediatric blindness most commonly occurs from corneal scarring and retinal diseases.

Studies have shown that ethnicity does not affect the incidence of ophthalmia neonatorum,
but socioeconomic status certainly does.

Ophthalmia neonatorum treatment:
o
Chlamydiae trachomatis: Oral erythromycin 50 mg/kg in four divided dose for 14
days
o
Gram-positive bacteria: Erythromycin 0.5% e/o QID
o
Gram-negative bacteria: gonococcal

Systemic: Inj. ceftriaxone 25–50 mg/kg IV or IM single dose X 7 days

Inj. cefotaxime 100 mg/kg IV or IM single dose X 7 days

Topical: saline lavage hourly, bacitracin eye ointment qid, or penicillin drops
5000-10,000 IU/ml

Worldwide, 135 million people have vision <20/60, and approximately 45 million have vision
<20/400. (?)

Eighty percent of global blindness either can be treated or avoided.
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
National Fortnight on Eye Donation is celebrated from 25th August to 8th September. Late
Prime Minister Shri Rajiv Gandhi pledged his eyes for donation on the 25th August to
motivate people. Since then a fortnight is celebrated every year.

Hospital Cornea Retrieval Programme
Ramayamma International Eye Bank initiated HCRP IN 1990 to concentrate on death that
occurs in hospitals and encourage eye donations using a combined method of motivation
and grief counselling. HCRP focuses on hospital because:

o
Availabilty of medical history
o
Availability of tissues from younger individuals
o
Reduction of time interval between death and corneal excision
Childhood Blindness
o
Globally prevalence is 0.75/1000 children (75 per one million)-varied from .3 to
1.2/1,000 children.
o
1.4 million blind children in the world-1 million in Asia
o
Prevalence of childhood blindness in India: 0.17%
o
Refractive error is major causes: 33.3%

prevalence of uncorrected refractive error (myopia) among age groups 7 -15 years is around
7.3% in urban and 4% in rural.

The prevalence of ocular trauma in a study urban slums Delhi s= 2.4% (2008)
In South India (Andhra Pradesh Eye Disease Study) = 3.97% (2000)

Field of vision restricted to 20 degree around central fixation- equivalent to <6/60
Field of vision restricted to 10 degree around central fixation- equivalent to <3/60
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
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DR in community:
o
Prevalence of diabetes: 3% - 20%
o
Prevalence of diabetic retinopathy: 15 - 25%
o
Prevalence of sight threatening DR- 20%
o
Proportion of DR becoming blind- 2%
Blindness Prevalence:
o
Prevalence of blindness (1986-89)- 1.49%
o
Prevalence of Blindness ( 2001-02)- 1.1%
o
Percentage of decline of Prevalence – 26%
o
Percentage of blindness due to Cataract (1986-89) – 80 %
o
Percentage of blindness due to Cataract (2001-02) – 62 %
o
Cataract blindness as per NPCB criteria in 50+population- 5.32% (8 % as per 198689 Survey)
o
Cataract surgical coverage – 65.7%
o
16.6% individual are socially blind after cataract surgery.
o
33.6% presenting vision < 6/60 after cataract surgery
NPCB Financial Assistance:
o
NPCB Supports Rs. 2000/- per pair of eyes collected
o
Rs. 275 per spectacle by NPCB
o
Assistance for Cataract Surgery @ Rs.1000/- per cataract operation/per eye
o
Assistance of Rs. 1500/- per case for management of diseases like diabetic
retinopathy, glaucoma, childhood blindness including squint and ROP etc
o
Assistance of Rs. 5000/- per case for corneal transplantation, vitreo-retinal surgery
o
Rs.30 Lakhs to NGOs for insfrastructures development
o
To Eye Banks in Government/Voluntary Sector (upto maximum Rs. 15.00 lakhs);
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o
Eye Donation Centres in Government/Voluntary Sector (upto maximum Rs. 1.00
lakhs).
o
Development of Mobile Ophthalmic Units with Tele-Ophthalmic Models (upto
maximum Rs. 60.00 lakhs).
o
Assistance for Mobile Van with ophthalmic equipments Rs.20 lakh.
o
Tele- Ophthalmic Network Rs.40 lakh
NPCB-100% centrally sponsored
In 1994-95, Program was decentralized with formation of DBCS


Proposed structure for Vision 2020 (4 Tier structure)
o
Centre's of Excellence: 20, One for 50 million
o
Training Centre's: 200, One for 5 million
o
Service Centre's: 2000, One for 5 lakhs
o
Vision centre's: 20000, One for 50,000
Ophthalmologist:1 per 50,000 population
MLOA: 1 per 5,00,000 population

India Study of Age-related Eye Disease (INDEYE study) (RPC and LAICO)
o
Prevalence of cataract in 60+

Men: 70.1 (68.0-72.1)

Women: 76.7 (74.9-78.5)

Total: 73.6 (72.0-75.2)

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Miscellaneous


Preparation of tissue for EM:
o
Primary fixation: 2.5% glutaraldehyde in distilled water
o
Wash: distilled water
o
Secondary fixation: 1-4% osmium tetroxide in distilled water
o
Wash: distilled water
o
Dehydration: 70% ethanol
Oculo Cutaneous Albinism
o
o
OCA1: TYROSINASE-NEGATIVE OCA

AR

Classic and most severe form

second most common type of OCA

do not have clinically or histopathologically discernible pigmentation

In vitro hair bulb incubation in L-tyrosine does not produce melanin.

skin and hair reveals no melanization of melanosomes.

decreased number of crossing nerve fibres at the optic chiasm, as well as
other central visual pathway anomalies.

Not associated with syndromes
OCA2: TYROSINASE-POSITIVE OCA

AR

most common form of albinism
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
presence of some pigment in the hair, skin, and eyes of all patients beyond
infancy

lightly melanized melanosomes in the skin and hair of older patients

maps to 15q11

region associated with Prader-Willi's and Angelman's syndrome

Chediak-Higashi and Hermansky-Pudlak syndromes are potentially lethal
forms of albinism, both of which are inherited in an autosomal recessive
fashion.

Chediak-Higashi syndrome is characterized by neutropenia, lymphocytosis,
anemia, and thrombocytopenia. Neutrophils and other lysosome-containing
cells characteristically have large granules and have impaired chemotaxis
and microbial killing caused by poor fusion of lysosomes to phagosomes.
Patients suffer from recurrent infections and are at increased risk of
developing lymphoreticular malignancies.

Hermansky-Pudlak syndrome is more common in Puerto Ricans, and
patients with this syndrome have abnormal platelets and a susceptibility to
bleeding and bruising.
Ocular Albinism:
o
XR
o
Nettleship–Falls type
o
eyes show hypomelanosis with nystagmus, and the hair and skin have no or little
clinical manifestation
o
mother is carrier
o
Five tests can be performed to diagnose XLOA or to detect the carrier state: iris
illumination, fundus examination, skin biopsy, VEP, and DNA tests
Latest Nosology of Albinism
OCA 1: tyrosine related (HPS,CHS)
OCA 2: p gene
OCA 3: TYRP1
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OCA 4: MATP
OA 1: XL

The hallmark of nasopharyngeal carcinoma is its propensity to involve multiple cranial
nerves noncontiguously.

There are nine distinct subtypes of EDS but type 6 and, rarely, type 4, are associated with
ocular features.

Eye-Protective Mechanisms

o
Tear production
o
Blink frequency and adequacy
o
Eyelid movement and position
o
Corneal sensation
o
Ocular motility
o
Bell's phenomenon
Gadolinium and fat suppression are T1 techniques and both should be used together as
no use of giving only gadolinium.
FLAIR is T2 technique that suppreses water (CSF). It may be confused with T1.

Most of orbital mass are dark (hypointense) on T1 MRI
Exceptions are  Fat, Blood and melanin
o
Fat: lipoma, liposarcoma
o
Mucus: dermod cyst, mucocele
o
Subacute blood (3-14 day old)
o
Melanin: melanoma
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o
Some fungal infections
o
Gadolinium enhancement
o
Retinoblastoma also hyperintense on T1
Dhaval Patel MD
Ophthalmic association of OSA
o
Floppy Eyelid Syndrome
o
CPAP associated red eye
o
NAION
o
Papilledema
o
Normal Tension Glaucoma

Heavy eye syndrome: This condition occurs when the globe enlarges on the basis of axial
myopia. This globe enlargement results in dehiscence of the intermuscular membrane in the
superior temporal area which in turn results in the superior rectus shifting nasally and the
lateral rectus inferiorly. In some cases the eye is also hypodeviated in this condition. A
relatively new procedure described by Yokoyama unites the belly of the nasally displaced
superior rectus muscle with the inferiorly displaced lateral rectus with reported good results.
If the medial rectus is tight, it could be recessed or some would consider the use of Botox.

Hutchinson‘s pupil: Fixed, dilated pupil in comatose patient due to uncal herniation and
compression of cranial nerve III
Hutchinson‘s sign: Involvement of tip of nose in herpes zoster ophthalmicus (nasociliary
nerve involvement)
Hutchinson‘s triad: Three signs of congenital syphilis – interstitial keratitis, notched teeth,
and deafness

In USG, Gain adjusts the amplification of the echo signal, similar to volume control of a
radio. Higher gain increases the sensitivity of the instrument in displaying weak echoes such
as vitreous opacities. Lower gain only allows display of strong echoes such as the retina and
sclera, though improves resolution because it narrows the beam.
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
Ophthalmia nodosa is a cutaneous condition characterized by inflammation of the eye due
to lodging of (for example) caterpillar hairs in the conjunctiva, cornea, or iris.

Ophthalmomyiasis:
Myiasis is coined from the Greek word ‗myia‘ denoting fly. It refers to the infestation of
tissues by the larvae (maggots) of diptera (two-winged) flies. The condition is well
recognised in animals but rare in humans. Cases of human myiasis have been reported in
various parts of the world and could be attributed to one of the three dipteran families:
Oestriade, Calliphroidae and Sarcophagidae.
In South-East Asia, animal myiasis is endemic and the main causative agent is Chrysomya
bezziana, also known as screwworm fly of the Old World. This fly belongs to the
Calliphoridae family and causes obligatory myiasis (it requires a living host for the
development of the larval stages). It infests mainly domestic animals and may cause great
losses in livestock industry if not treated rapidly.
Screwworm infestation is transmitted by the female fly that lays her eggs on a superficial
wound, but occasionally on unbroken soft skin, especially if it has blood or mucous
discharge on its surface. Eggs are deposited in batches of 150 to 500 and hatch in about 15
hours. The larval bodies, measuring 10 to 15mm are armed with broad, encircling bands of
spines. The larvae feed on blood and serum and burrow deep into the tissue with their
mouth-hooks causing considerable destruction. Infested wounds often attract other female
screwworms resulting in multiple infestations. After feeding for 5 to 7 days, the larvae leave
the wound and fall to the ground where they burrow and pupate for one week or more to
emerge as adult flies. The life cycle from egg to egg takes about 24 days.
The sclera of a child is easier to penetrate than that of an adult.

After thyroidectomy, the complication can be hypoparathyroidism with consequential
hypocalcaemia leading to cataract and corneal clouding. Ca2+ ions are essential for corneal
metabolism-note the sub-epithelial clouding.

Draize eye test: Justified by an exigency for public protection, the Draize eye test became a
governmentally endorsed method to evaluate the safety of materials meant for use in or
around the eyes. The test involves a standardized protocol for instilling agents onto the
cornea and conjunctiva of laboratory animals. A sum of ordinal-scale items of the outer
eye gives an index of ocular morbidity
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The hallmark of nasopharyngeal carcinoma is its propensity to involve multiple cranial
nerves noncontiguously. Nasopharyngeal carcinoma is common in Chinese men. The least
differentiated forms are also known as Schmincke's and Regaud's tumors.
NPC has its highest incidence in southern China escpecially in Hong Kong and Guangzhou,
with documented rates of 10 to 150 cases per 100,000 population per year. For this reason,
this cancer is often referred to as "Cantonese cancer" or "Kwangtung tumor."

Apart from hypertensive choroidopathy, decreased vision in eclampsia (also in
preeclampsia) are usually caused by:
o
serous retinal detachment (from the breakdown of the retinal pigment epithelium
barrier)
o
occipital cortex involvement (this may be caused by vasospasm, ischaemia or
oedema from increased vascular permeability, most cases of cortical blindness
resolved within 4 hours to 8 days)
Less common causes include:

acute ischaemic optic neuropathy

retinal vasospasm or oedema

It was thought at the time that animal eyes actually generated light and that the more excited
the animal, the brighter the light. This idea was ultimately put to rest by Prevost (1818) who
showed that one never saw a luminous eye when the animal and observer were in a totally
dark room. At about the same time Gruithuisen discovered that the eyes of some animals
(e.g., dogs and cats) contain a unique layer behind the retina, the tapetum lucidum that
reflects light and is responsible for the luminous appearance of animal eyes.

Key idea in the invention of the ophthalmoscope: the illumination axis and the observer‘s
viewing axis have to be as close as possible.

Since the maximum resolving power of the direct ophthalmoscope is 60 µm, many of
the small red dots observed in the fundus are not microaneurysms but microhemorrhages.
The effect of body size as a risk factor for primary open angle glaucoma (POAG) is unclear.
In fact, the Barbados Eye Study found that lean body mass may be a risk factor for
POAG in the African American population.
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
The Singaporean Chinese community, in particular, has a very high incidence of primary
angle-closure glaucoma.

Echothiophate iodide is an irreversible cholinesterase inhibitor whose effects may persist
for days after discontinuation of the drug. It prolong respiratory paralysis caused by SCh.

Mydriatic recovery in normal eyes is as follows: atropine (7-10 days), scopolamine (3-7
days), homatropine (1-3 days), cyclopentolate (1 day), and tropicamide (6 hours).

Cyclosporine is a potent immunosuppressive agent that acts by suppressing T cells. This
is helpful in many ocular surface conditions from atopic keratoconjunctivitis to dry eyes to
graft rejection.

The IOP-elevating potential, in decreasing order, is dexamethasone > prednisolone >
loteprednol etabonate > fluorometholone > hydrocortisone > tetrahydrotriamcinolone.

Ciprofloxacin has broad gram-positive and gram-negative bacterial activity by interfering
with DNA gyrase; however, recent reports have described the growing resistance of
streptococci to ciprofloxacin.

Natamycin is available as a 5% topical ophthalmic solution. It is active against filamentous
fungi including Aspergillus, Cephalosporium, Curvularia, Fusarium, Penicillium, and Candida
albicans. Mucor is better treated with amphotericin B.

Proparacaine is a topical ester anesthetic. Its duration of action is about 20 minutes**. In
injectable form, lidocaine lasts 1 to 2 hours, mepivacaine lasts 2 to 3 hours, and bupivacaine
(Marcaine) lasts up to 8 hours.
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
During the procedure C3R, 0.1% Riboflavin eye drops in Dextran solution are applied to the
cornea for 30 minutes followed by exposure to UV-A light (365 nm) at 3mW/cm2 to achieve
cross-linkage of the corneal collagen fibres.

The term lagophthalmos comes from the Greek word for hare (lagos) because rabbits
were thought to sleep with their eyes open.

Color blindness was not recognized as a congenital defect until 1794 when the famous
chemist John Dalton described his own red-green deficiency.

Cost-Effective Eye Care: Avoid These 5 Tests and Treatments
1. "Preoperative Medical Tests: Don't perform preoperative medical tests — such
as an electrocardiogram or blood glucose test — prior to eye surgery unless
there are specific signs indicating a need for them.
2. Imaging Tests: Don't routinely order imaging tests when there are no symptoms
or signs of significant eye disease.
3. Antibiotics for Pink Eye: Don't prescribe antibiotics for pink eye that is caused by
an adenovirus.
4. Antibiotics for Eye Injections: Don't routinely provide antibiotics before or after
injections into the vitreous cavity of the eye.
5. Punctal Plugs for Dry Eye: Don't treat dry eye by inserting punctal plugs before
attempting other options, such as medical treatments with artificial tears,
lubricants and compresses."

AD/ MCI/ Normal Cognition: Patients with probable AD had significantly narrower retinal
veins and decreased retinal blood flow compared with those with MCI and normal controls.
But the MCI group had significantly lower blood flow and blood speed than those with
normal cognition.

Bionic Eye: US Food and Drug Administration (FDA) approved a retinal prosthesis that
may help blind people with advanced-stage retinitis pigmentosa avoid obstacles and read
large letters. It does not restore normal vision, but it does produce patterns of light that the
brain learns to interpret as specific objects in the environment
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
Taiwanese researchers developed a fungus-specific oligonucleotide probe for a molecular
hybridization assay to look for a conserved region of the 5.8S rRNA gene common to
various fungi species. The hybridization assay identified the fungi species within 1 day and
had a sensitivity of 100% and specificity of 96.7%, compared with 50% sensitivity and 100%
specificity for cultures

Sweet syndrome: key clinical features in this case are the abrupt onset of fever, bilateral
ocular inflammation nonresponsive to topical steroids, and tender skin nodules in a
patient with a known diagnosis of ulcerative colitis. Two features are absolutely required for
diagnosis: the abrupt onset of a typical skin eruption that consists of tender erythematous
plaques, nodules, or pustules, and the histologic finding of neutrophilic infiltration in the
dermis without leukocytoclastic vasculitis on skin biopsy.

surfaces of the globe and cornea: 12000 km & 12000 microns

Glues used in Ophthalmology
o
o
Fibrin  conjunctival closure

Antibiotic impregnated

Pterygium  Graft

Clear corneal incisions

Ptosis: Muller conjunctival resections
Tranforming growth factor beta

o
Chorioretinal adhesion
Cyanoacrylate

N-butyl-2-cyanoacrylate  clear corneal incisions

Octyl-2-cyanoacrylate

Adal-1 cyanoacrylate

Iso-amyl-cyanoacrylate
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
experimental use of oral rifampin and mifepristone (RU486) has recently been suggested
especially in chronic or bilateral cases of CSCR.

investigational drug selumetinib, an MEK inhibitor under development by AstraZeneca,
systemic therapy has shown efficacy in a rare form of melanoma that affects the eye, uveal
melanoma.

An ancient eye test-using the stars: Vision testing in ancient times was as important as it
is today. The predominant vision testing in some cultures was the recognition and
identification of constellations and celestial bodies of the night sky. A common ancient
naked eye test used the double star of the Big Dipper in the constellation Ursa Major or the
Big Bear. The second star from the end of the handle of the Big Dipper is an optical double
star. The ability to perceive this separation of these two stars, Mizar and Alcor, was
considered a test of good vision and was called the "test" or presently the Arab Eye Test.
This article is the first report of the correlation of this ancient eye test to the 20/20 line in the
current Snellen visual acuity test. This article describes the astronomy, origin, history, and
the practicality of this test and how it correlates with the present day Snellen visual acuity
test.

Fishhook contains the barb at its end, so once inside, it‘s difficult to remove it in cases of
eye injury.

Glaucoma Research Foundation (GRF): 2011, Researchers employed a range of
techniques including molecular biology, electron microscopy and image analysis to uncover
three interconnected new discoveries about glaucoma: Glaucoma Reveals New Similarities
to Parkinson's Disease: Glaucoma is characterized by formation of protein aggregates
called gamma-synuclein. Most other neurodegenerative disorders, like Parkinson's and
Alzheimer's diseases and Amyotrophic Lateral Sclerosis (ALS), are characterized by the
aggregation of proteins. In Parkinson's disease, a very similar protein called alphasynuclein is aggregated. This finding provides evidence that glaucoma acts more like
protein aggregation neurodegenerative diseases than like other blinding eye diseases. New
Cellular Mechanism Discovery: A subpopulation of support cells, called astrocytes, have
been found to have a highly unexpected role in cleaning up the byproducts or waste of the
cells that die in glaucoma, the retinal ganglion cells. This type of "degradative" activity was
not previously known to exist, and its existence may help explain perplexing findings in
many neurodegenerative disorders besides glaucoma. Underlying Cause of Vision Loss:
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Previous work by scientists had pointed to an anatomical location, the optic nerve head,
where vision loss most likely occurs in glaucoma. This study is the first to pinpoint where
within the optic nerve head the blinding insult is likely to be, which would explain the very
characteristic pattern of blindness in glaucoma

AAO Suggested Routine Eye Examination Guidelines
Ages 0-2: screening during regular pediatric appointments.
Ages 3-5: screening every 1–2 years during regular primary care appointments.
Ages 6–19: schedule examinations as needed.
Ages 20–29: one examination
Ages 30–39: two examinations
Ages 40–65: examination every 2–4 years
Ages 65 and over: examination every 1–2 years.
(More frequent examinations may be recommended if any of the following risk factors
exist: history of eye injury, diabetes, family history of eye problems, African Americans
older than 40 years of age.)

In shaken baby syndrome, Neurological deficits occur in about one-third of patients.
Visual impairment is usually caused by cerebral damage.

Ramsey Hunt syndrome:
Sudden onset of pain in the ear and who cannot shut the eye on the same side.
The involvement of the seventh cranial nerve with the herpes zoster virus. There may be an
eruption in the external auditory meatus, as this area receives a sensory supply from the
seventh cranial nerve.

Paget's disease:
the patient who need a bigger hat develop an afferent pupillary defect
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This causes enlargement of the skull due to disorganization of the bony structure. This can
cause compressive optic atrophy in the optic canal.

Visual claudication
woman complains of discomfort in both arms and a transient loss of vision which occurs on
exercises
Takayasu's syndrome with involvement of the carotid and axillary arteries. Exercise
causes a "steal" syndrome leading to retinal ischaemia.

VITAL Study: VIsion TriAL for depression management, related to low vision aids.

Charles Bonnet syndrome:
o
condition that causes patients with visual loss to have complex visual
hallucinations, first described by Charles Bonnet in 1760 and first introduced into
English-speaking psychiatry in 1982.
o
Sufferers, who are mentally healthy people with often significant visual loss, have
vivid, complex recurrent visual hallucinations (fictive visual percepts). One
characteristic of these hallucinations is that they usually are "lilliputian"
(hallucinations in which the characters or objects are smaller than normal). The most
common hallucination is of faces or cartoons. Sufferers understand that the
hallucinations are not real, and the hallucinations are only visual, that is, they do not
occur in any other senses, e.g. hearing, smell or taste

Serif fonts and Sans Serif fonts are two broad categories of letters.

National Institute for the Visually Handicapped NIVH is situated at 116 Rajpur Road,
Dehradun - 248 001, Uttaranchal, India. Phone: + 91 135 274 4491

Coenurosis is a parasitic infection that results when humans ingest the eggs of dog
tapeworm species Taenia multiceps, T. serialis, T. brauni, or T. glomerata. There are many
different tapeworm species belonging to the genus Taenia, but these four in particular are
responsible for the rare human disease, coenurosis.
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
In 1974, US National Institutes of Health held a conference on the naming of diseases and
in 1975, JAMA published an article and decided to drop the possessive ―s‖ in all its
publications (Down syndrome not Down‟s Syndrome) but has not been able to convince
journal editors.

Tyndall effect: A very sensitive way to detect particulates is to bathe the air with intense
light. The scattering of light by particulate impurities in air and other gases, and in liquids, is
known today as the Tyndall Effect or Tyndall Scattering.

ALARA concept: As Low As Reasonably Achievable, for radiation exposure in imaging.

HEPA filters remove particles <0.3 microns.

blood level of vitamin A: 150–300 IU/dl (30–65 µg/dl retinol)

Uyemura‘s syndrome: xerophthalmic fundus, White spots of the fundus combined with
night blindness and xerosis

detection of foreign body based on electrical conduction

o
Bermann‘s locator
o
Roper Hall‘s locator
o
Carnays locator
o
Ophthalmometalloscope of Hale
Limbal ring method for detection of FB was described by Stallard and Somerset. It was
used basically to detect FB is intraocular or extraocular.
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types of magnets
o
Hand held RARE EARTH magnet: small and low powered.
o
Electromagnet: strong magnetic field
FUGO Blade:
o ―electromagnetic plasma‖ cutting device
o developed by an ophthalmic surgeon, Dr.Richard Fugo
o It works on 4 rechargeable battery cells. One charge allows a cutting time of 40
minutes
o The working end of the tool is the blunt tip of a steel wire, varying in size from 100
micron to 600 microns
o plasma energy from the activated working tip is transferred to the molecules of the
tissues, by the process of resonance

Mast cell inhibitors
o
Lodoxamide (Alomide)
o
Cromolyn sodium (Crolom)
H1 receptor antagonists
o
Levocabastine (Livostin)
o
Emedastine (Emadine)
Combination H1 antagonists/mast cell inhibitors
(POKAN)
o
Ketotifen (Zaditor)
o
Olopatadine (Patanol)
o
Nedocromil sodium (Alocril)
o
Azelastine hydrochloride (Optivar)
o
Pemirolast (Alamast)
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
Echothiophate iodide is an irreversible cholinesterase inhibitor whose effects may persist for
days after discontinuation of the drug.

Ciprofloxacin has broad gram-positive and gram-negative bacterial activity by interfering with
DNA gyrase; however, recent reports have described the growing resistance of
streptococci to ciprofloxacin.

The eye-popping reflex is a neonatal reflex described by Perez in 1972. It involves a
pronounced widening of the palpebral fissures after an abrupt decrease in ambient
illumination primarily, or after loud noises. It is present within the first 3 weeks of life in 75%
of infants born after 28 weeks' gestation.
In contrast, eye pressing, or gouging, and light gazing are abnormal behavioral
mannerisms in visually-impaired children.
A paradoxical pupillary response is rare but when present, it is highly suggestive of
congenital stationary night blindness, achromatopsia, or optic nerve hypoplasia. A
paradoxic response refers to an immediate constriction during the first 20 seconds after
room lights are turned off, followed by a slow dilation after 1 minute.
Lateral Thinking

Stigler's Law of Eponymy, which states, "No scientific discovery is named for the
original discoverer" As proof, Stigler freely admits that others postulated the idea before he
named it for himself.
In describing Stigler's Law, Malcolm Gladwell stated, "We think we're pinning medals on
heroes. In fact, we're pinning tails on donkeys.‖

"Domino" effect: chain reaction that occurs when a small change causes a similar
change nearby, which then causes another similar change, and so on in linear sequence.
The term is best known as a mechanical effect, and is used as an analogy to a falling row
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of dominoes. It typically refers to a linked sequence of events where the time between
successive events is relatively small. It can be used literally (an observed series of actual
collisions) or metaphorically (causal linkages within systems such as global finance or
politics).

Butterfly effect is the sensitive dependency on initial conditions in which a small change at
one place in a deterministic nonlinear system can result in large differences in a later state

Lewis Carroll conceives of Alice seeing things smaller than they were was because of
Migraine in which he had episodes of micropsia during his migraine attacks.

Vision of Quicksands: Thomas de Quincey experienced visions of a girl sinking in
quicksands while he was under the influence of opium.

licensed ophthalmologist: Syria‘s President Bashar al-Assad, and Kentucky Senator
Rand Paul

Turk disease is another name of Duane Retraction Syndrome.

Strumple Marie Disease is another name of Ankylosis Spondylitis.

The concept of removing clouded cornea was described by Erasmus Darwin, grandfather
of Charles Darwin.

Twilight Blindness or Aknephascopia is an abnormally reduced vision in low level of
illumination.

Samuel Thomas van Sommerring was a german anatomist, who first described
importance of macula and in older literature, macula is also referred as Sommerring‘s
spot.
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Sir jonathan Hutchison was an English surgeon, ophthalmologist, dermatologist,
venerologist and pathologist.
o
Senile Degeneration of choroid is known as Hutchinson's disease
o
Hutchinson's facies is a peculiar, rigid facial expression produced by drooping
eyelids and unmoving eyes.It occurs due to tension of the muscles of the forehead
attempting to counterbalance ptosis in external ophthalmoplegia

William Conner and Richard Alexander started a small pharmacy  Alcon (AL from
Alexander and CON from Conner, in texas in 1949 making sterile medical appliances and
drugs. It grew over time and was bought by a swiss company and sold off again recently to
NOVARTIS as one of the biggest business deal 28 billion USD.

ALLERGAN:
The innovative spirit that infuses Allergan today can be traced back to Allergan's founder,
pharmacist Gavin S. Herbert. In 1948, Mr. Herbert was already the successful owner of a
chain of drug stores in Los Angeles. But his interest and entrepreneurial instincts were
ignited when a close friend and chemist, Stanley Bly, approached him with an idea for an
anti-allergy nose drop containing the antihistamine neoantergan (aka MEPYRAMINE).
They set up a small laboratory on the balcony of Mr. Herbert's drugstore in Los Angeles to
make the solution, which they named ALLERGAN® Nasal Drops. Responding to the
suggestion of an ophthalmologist friend, Mr. Herbert and Mr. Bly later reformulated the
product as an eye drop to treat allergic conjunctivitis (inflammation of the eye). The result
was ALLERGAN®, the first antihistamine eye drop in the United States.

Norma Jeane Mortenson became Marilyn Monroe after cosmetic –aesthetic surgery.

Literal meaning of cul-de-sac is a road with one end blocked or dead end.

In 1850s, ―Eye Mirror‖ or ―Eye Speculum‖ was a popular name for an emerging
ophthalmic instrument among the Europe  augenspiegel (german name of eye mirror)
which later become ophthalmoscope.
o
Augenspiegel (eye mirror) and Augenspiegeln (eye mirroring).
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The word ophthalmoscope was first introduced by Maressal de Marsilly from Calais,
France, in 1852.

The term daltonism was described for color blindness of John Dalton, the great chemist
who first described his own anomaly.

Duke-Elder in 1936 honored Sjogren by naming KCS with Sjogren‘s Syndrome.

It was Sir Isaac Newton who first proposed that binocular vision results from partial
decussation of optic nerve fibres at optic chiasm.

Another term suggested for ICE syndrome is NUDE syndrome..!! (not approved still) Now
the syndrome described by Al Reese and me is characterized by nodules, unilateral
glaucoma, Descemet's membrane and endothelial extension; why not call it by the acronym
NUDE syndrome.

Elschnig:
o
Elschnig's pearls (Elschnig's bodies): Pearl-like clusters formed by growth of
Equatorial epithelial cells onto the posterior lens capsule of the eye following cataract
surgery. (A type of After cataract)
o
Elschnig's conjunctivitis: Chronic conjunctivitis associated with hyperplasia of the
tarsal gland and the frothy secretions.
o
Elschnig's spots: In malignant hypertension, blood vessels in Retina& Choroid may
be damaged leading to fibrinoid necrosis(presence of fibrin thrombi in vascular
lumen). So when choroid vessels are damaged, it produces choroidal infarcts&
necrosis of overlying Retinal Pigment Epithelium (since the outer 4 layers of retina
are supplied by Choriodal blood vessels).These spots appear as small isolated
circular areas having central retinal pigment, epithelial pigment clumping, and a
surrounding halo of de-pigmentation.These are known as Elschnig spots.(So seen
when choroidal blood vessels damaged in Malignant hypertension-Hypertensive
choriodopathy)
o
Z-plasty (Elschnig's operation): It is useful to correct mild to moderate degree of
cicatricial Ectropion.
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o
Elschnig's syndrome (Elschnig‘s complex): Also known as Blepharo-cheilodentin (BCD) syndrome. Features include ectropion of lower eyelids, distichiasis of
upper eyelids, euryblepharon(symmetrical enlarge-ment of the palpebral aperture
associated with large eyelids), bilaterally cleft lip/palate, oligodontia, and conical
crown form. Initially known under the eponym Elschnig syndrome.
o
Elschnig's theory: Elschnig suggested the anaphylactic theory of the pathogenesis
of sympathetic ophthalmia. According to this theory, it is not a question of a particular
infection, but of an anaphylactoid inflammation against the body‘s own uvea tissue.
Under certain conditions, uvea tissue damaged by trauma will act as an antigen and
subsequently occasion a sensibilisation of the body‘s own uvea albumin. This causes
an anaphylactic uveitis on the undamaged eye.
o
Elschnig's intracapsular forceps: fine untoothed forceps for holding tissue, swabs,
sutures, etc; removing things like clots, capsule fragments, lens, etc; used in cataract
surgery
o
Elschnig's scleral ring: Scleral ring is a white circular band that separates the
intrapapillary region of optic disc from the peripapillary area.The scleral ring itself
does not belong to optic disc.This is important for all optic disc measurements
because the inclusion of scleral ring as part of optic disc falsely enlarges the
neuroretinal rim & decreases cup/disc ratio.Loss of nerve fiber layer in Glaucoma
can make the scleral ring more visible due to loss of overlying tissue.
Vogt:
o
Vogt white limbal girdle: Age related corneal degeneration, Characterized by
bilateral, narrow cresentic lines composed of chalky white deposits(present in
Bowman‘s membrane) in the interpalpebral fissure along the nasal& temporal limbus.
o
Vogt's striae: Seen in keratoconus, With thinning of the cornea vertical lines in the
Descemet's membrane become visible. They disappear with pressure on the globe
o
Vogt's anterior mosaic crocodile shagreen: Age related corneal degeneration,
Anterior mosaic crocodile shagreen appears as bilateral, polygonal, grayish-white
opacities separated by relatively clear spaces in the deep layers of the epithelium
and in Bowman's layer
o
Vogt-Koyanagi-Harada (VKH) syndrome: Vogt-Koyanagi-Harada (VKH) disease is
a multisystem disorder characterized by granulomatous panuveitis with exudative
retinal detachments that is often associated with neurologic and cutaneous
manifestations.
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Lucid interval of vogt: Seen in Arcus senilis(Age related corneal degeneration),
Arcus senilis appears as a single greyish ring compose of lipid deposits parallel to
the limbus and separated from it by a 1 mm lucid interval of Vogt, The classic theory
concerning the appearance of arcus cornealis is that lipids migrate from the limbal
vascular arcade to the peripheral cornea and the clear interval of Vogt is formed due
to absorption of the lipids that are closer to the vascular arcade.

Ophthalmic conditions having Cogan's name - Cogan's congenital oculomsotor apraxia,
Cogan's lid twitch, Cogan's microcystic dystrophy, and Cogan's syndrome.

Arctic explorer develops disc swelling due to Vitamin A toxicity from eating polar bear
liver. The liver of polar bear is dangerously high with vitamin A.

Acute angle closure glaucoma can present with abdominal pain with nausea and
vomiting.

Crocodile Tears: Following damage to the facial nerve as in Bell's palsy, misdirection of the
regenerating fibres may innervate the lacrimal gland rather than the mouth muscles and the
parotid glands. Consequently, chewing food causes weeping. Legend has it that the
crocodile has compassion and remorse for its prey and wept with sorrow when it eats its
prey.

Bungee jumper with blurred vision: Valsalva's retinopathy. The build-up of pressure in
the venous cava causes the retinal vein to burst and produce haemorrhage.

Tool maker's eye: Argyrosis. It is a term applied to the deposition of silver salts in the
tissue. In the conjunctiva, the deposition of silver turns black on oxygenation.

Famous Victorian writer who is also an ophthalmologist: Sir Arthur Conan Doyle, the
creator of Sherlock Holmes. Apparently not a good one, as he had plenty of time for writing
due to lack of patients.
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
Albert Einstein's eyes were removed by his ophthalmologist Dr. Henry Abrams during the
autopsy in 1955 and stored in a safety deposit box. The eyes were put up for auction in
1994.

Uvea means a grape. The term was first used by Galen, a Roman physician to include both
the choroid and the iris because they resemble a grape from which the stalk had been torn
out leaving a hole in front, the hole being the pupil of the eye.

Carotid is derived from a Greek word meaning "to put to sleep" because pressure on the
carotid arteries can cause loss of consciousness. Rufus of Ephsus said (about 100 AD):"
The ancients called the arteries of the neck carotid because they believed that when they
were pressed hard the animal became sleepy"

Atropine poisoning: "hot as a hare, blind as a bat, dry as bone, red as a beet, mad as a
hen".

down-and-out went blind because of Ingestion of methylated spirit. Methylated spirit
contains 5% methanol and 95% ethanol. When drunk for its ehtanol content, the breakdown
products of methanol are extremely toxic to the eye causing optic atrophy

coast of Maine:
Fibrous dysplasia (Albright's syndrome)
It is characterized by osteitis fibrosa disseminata, areas of pigmentation and endocrine
dysfunction, with precocious puberty in females. The borders of the pigmentation has an
irregular or jagged edge (coast of Maine). The involvement of the orbit can lead to
shallowing and proptosis.

coast of California:
Neurofibromatosis.
The pigmentation has a smooth edge (coast of California). In some patients, the congenital
absence of sphenoid bone leads to encephalocele and proptosis
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
Iago blandly warns Othello that jealousy is "a green-eyed monster which doth mock the
meat it feeds on." In China, covetousness is "red-eye disease".

H.G.Wells‘ one of the story, a sighted man fell into the Valley of the Blind and fell in love
with a blind girl. When faced with the threat of losing his sight, he fled. The famous quote is
in the country of the blind, the one-eyed man is King.

Ella Wheeler Wilcox (1850-1919): Laugh, and the world laughs with you; Weep, and
you weep alone

Ovid advised man to shed tears. "They move the most adamant natures. Let her, if
possible, see tears on your cheeks, in your eyes." And if you can't produce tears at will, he
says, bring a vial of water and fake it.

Darwin observed that the English wept less than the Mediterranean.
One recent survey found that Israelis cry less than Britons, possibly, the authors
suggest, because of mandatory military service in Israel, which "encourages an active
and resourceful approach to the solution of problems and produces someone better able
to cope with difficulties.
Women cry more often and longer than men. In one study they wept 5.3 times a
month, compared to 1.4 for men. They also use tears more commonly as a coping
device, to win sympathy and shame malefactors.
Grief is not the sore cause of tears. Glory, success after extreme effort, can bring
tears. Perhaps the oddest of all, music can cause tears. One duct-squeezing trick entails
repeating a musical theme a step higher or lower than when the listener first heard it, as
in Albinoni's Adagio for Strings. Another, even more effective, is the appoggiatura, or
delay in resolving a musical theme. The Beatles' "Yesterday" begins with one, and
appoggiaturas abound in tear jerking tunes. They build a kind of anxiety, which the
melody finally resolves

In La Vita Nuova, Beatrice flashes love from her eyes and inflames Dante.
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Love at first sight usually involves eye contact, and the Greek poet Meleager (1st
century B.C) placed Cupid inside the eyes, whence he aimed his barbs. In much
subsequent lover poetry, and later among Arab poets and Provencal Versifiers of the 12th
century, the eyes shoot arrows, darts, or fiery beams that wound the soul and infect with
longings

BACCIO BANDINELLI Vasari describes repeatedly the poor color quality of Baccio‘s
paintings, but without specifying why. The paintings tend to use a monochrome yellow or
ochre for flesh tone.

EAGLES HAVE TWO FOVEAS: One fovea optimizes monocular vision to the side and the
other optimizes binocular vision to the front. An extremely soft lens of the eye allows for
rapid accommodation

Valetudinarians are sometimes confused with hypochondriacs. They couldn't be more
different. The hypochondriac thinks he's always ill, but the valetudinarians takes excessive
care to make sure that he doesn't fall ill.

Artificial electric eye: developed by William dobelle, in USA. It iacamera implanted on
spectacles with electrodes on retina.
The Class Questions

What are the causes of cyclotorsion in supine position?
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o
This is the fact which you will use in Toric IOLs and all your other kind of LASIK
procedures. The reasons I found are..
o
unmasking of cyclophoria during monocular fixation (Tjon-Fo-Sang et al., 2002;
Borish & Benjamin, 2006)
o
fusion loss (Park et al., 2009; Hori-Komaii et al., 2007; Fea et al., 2006; Chernyak,
2004; Swami et al., 2002);
o
dynamic cyclotorsion: blurring of the fixation target happens during ablation (after
epithelium removal in surface ablation and following flap lifting in LASIK)
o
(average cyclotorsion resulting from the shift from the upright to the supine position is
about ±4°)
Why 30-1 field is not used?
30-1 program measures points along the vertical and horizontal meridian and then every 6°
(Fig. 6-20). The problem with this strategy is that the points along the horizontal and vertical
meridian may fall either on the affected or unaffected side. For example, in a patient with a
neuro-ophthalmologic deficit with a vertical field cut, points exactly on the vertical meridian
may either be seen or not seen and thus are not particularly helpful. Similarly, in the case of
optic nerve lesions, points along the horizontal meridian may either be seen or not seen,
making that particular row rather unhelpful. This problem was corrected with the -2 strategy.
For example, in the 30-2 program the points are tested 3° above and below the horizontal
meridian, 3° to the left and right of the vertical meridian, and then every 6° (Fig. 6-21). This
eliminates the ambiguity of the points that are tested right along the vertical and horizontal
meridian. In general, strategies using the -2 terminology are more appropriate than the -1
strategies for both optic nerve and neuro-ophthalmologic examination.

Why FADEN operation works only in direction of action of muscle?
Point of posterior fixation is new insertion for action. As antagonist entire muscle acts.
Therefore limits muscle only in field of action

Why capsular phimosis does not always occur?
Capsular opening wants to contract but zonules are opposing the force for it. So when
zonules becomes weak, capsular opening beigns to shrink.
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Why Myopia should be Slightly under Corrected?
Myopia is corrected with a concave lens. A concave lens is a minifying lens. More is the
power more is the minification caused by it. Thus myopia is always slightly under corrected
to avoid minification of image and consequent eyestrain symptoms. Also if
overcorrected, patient will use his or her accommodation to overcome it and it will give
eyestrain symptoms.

Why Hypermetropia should be Fully Corrected?
Hypermetropia should always be fully corrected so as to relax accommodation and avoid
eyestrain symptoms. This is much more important in case of a squint. However it should
be born in mind that correction is not done at the cost of producing eyestrain symptoms.

Why Presbyopia Should be Slightly under Corrected?
When we read near objects accommodation and convergence both are required.
Presbyopia is always under corrected so as to encourage accommodation.
Accommodation is accompanied by accommodative convergence. Thus patient does
not complain of eyestrain symptoms. Full correction of presbyopia causes eyestrain
symptoms due to lack of accommodative convergence.

Why sea/water is blue?
o
Multiple theories
o
Duane 2006: The longer wavelengths of light penetrate water more deeply than do
the short wavelengths and are eventually absorbed. The shorter wavelengths are
reflected about in the superficial layers of water and reflected back to the observer,
making the water appear blue. In addition, the water is illuminated by the blue sky.
Some of this blue light is reflected toward the observer, contributing to the blueness.
(This is not believed now.I checked in physics book and article)
o
Reflection of color of sky
o
coloration by dissolved impurities - Cu2+
o
Now it is proved that it is due to: The longer wavelengths of light like red and
orange are absorbed in superficial layers of water and short wavelengths like blue
penetrate better which then get reflected and this is how water appears blue.
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o
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Dhaval Patel MD
Latest theory just like above: intrinsic blueness of water is the only example from
nature in which color originates from vibrational transitions
How does accommodation ‗know‘ it has achieved the sharpest focus?
by a sensing system in the brain, However, some have suggested that the system takes
advantage of the naturally occurring chromatic aberration of the primate eye to fine-tune
focusing.

What happens if the cornea is spherical?
When light rays pass through a spherical refractive surface, the para-axial rays are less
refracted than the peripheral rays; that is because the angle of incidence (and therefore the
angle of refraction) is wider in the periphery than that in the para-axial part of the spherical
surface. This results in multi foci and is responsible for what is known as "spherical
aberrations."

Why in HZV, we start 800 mg five times a day?
In HZV, 800 mg five times a day Acyclovir is strted for the following reasons:

o
Virus shedding period is decreased
o
Healing is accelerated by 50 %
o
Postherpetic neuralgia is decreased
More regression after LASIK seen in Myopic or Heperopic LASIK?
Hyperopic LASIK.
Hyperopic LASIK almost always regresses after first year because
o
Latent hyperopia masked by accommodative spasm
o
Epithelial hypertrophy
o
Intrinsic biomechnical effect of hyperopic LASIK that results in mid peripheral
steepening and central flattening
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Why Does Cataract Surgery Lower IOP in Some Patients?
o
Exact mechanism by which this occurs is largely unknown
o
IOP reduction does not vary based on ethnicity
o
improved aqueous humor outflow through the trabecular meshwork, ie, increased
aqueous outflow facility.
o
Trabecular meshwork endothelial cells from glaucomatous eyes that were exposed
to ultrasound had increased interleukin-1α (IL-1 α), a stress hormone and pathologic
marker for primary open-angle glaucoma, through NFκB translocation from the
cytoplasm into the nucleus.
Latanoprost is one kind of gene therapy for glaucoma. How?
Metalloproteinase gene increased transcription in human ciliary muscle cells with
latanoprost is seen. (Weinrub RN, IOVS 2002:43)
Remodeling of ECM in the TM via MMP2 and MMP3

Povidone Iodine application before surgery:
Povidone–Iodine Antisepsis for Cataract Surgery and Ophthalmic Procedures (Scott
WJ AJO, Volume 151, Issue 5, May 2011, Pages 914)
In the operating room, a 5% polyvidone iodine solution must be applied on the eyelids and a
5% solution in the conjunctival sack, respectively, and should dry out for at least 3 minutes
to guarantee adequate disinfection

Interval between drops:
Drop size and initial dosing frequency problems of topically applied ophthalmic
drugs. (Sukhbir S Chrai. Journal of Pharmaceutical Sciences Volume 63, Issue 3, pages
333–338, March 1974)
Multiple drops administered at short time intervals have the advantage of increasing drug
concentration in the precorneal film but the disadvantage of considerable drug loss through
drainage, which for potent drugs can lead to systemic toxicity. When using radioactive
technetium (99mTc) as the test substance in unanesthetized albino rabbits, it was shown
that a 5-min interval between drops minimizes drainage loss of drug and the drug
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concentration buildup in the precorneal film as compared to the corresponding dosage
regimen of drops administered at shorter time intervals.
Important History

The term ―astigmatism‖ is the joining of ―a‖ and ―stigmata,‖ a term suggested by Dr. William
Whewell (1794-1866)

In 1837, the astronomer Sir George Biddle Airy made a cylindric lens and used it to
correct astigmatism.

History of JCC:
o
Stokes lens: consisted of two cylinders, one planoconvex and one planoconcave,
with flat surfaces approximated and arranged so that they could be rotated in
opposite directions.
o
Edward Jackson realized the instrument's potential for determining cylinder power
o
modified Stokes lens with axes fixed perpendicular to one another came to be
known as the ―Jackson crossed cylinder‖
o
W. H. Crisp, a more prolific writer, to bring this device to worldwide attention

In 1984, Mazzocco et al introduced the first foldable plate haptic silicone lens produced
by STAAR Surgical. It became known as the ―Mazzocco Taco‖ because of the way it
appeared when folded.

―One of the most important and challenging tasks in IOL power calculation is to predict the
ELPo for a given eye‖ - Dr. Haigis

Vitrectomy History
o
Machemar: introduction of pars plana vitrectomy in the early 1970s. Machemer
initially performed pars plana vitrectomy with the use of a 17-gauge (1.5mm
diameter) multifunctional instrument capable of cutting and aspirating the vitreous.
This instrument utilized a fiberoptic sleeve and required a 2.3mm scleral incision.
o
In 1974, O‘Malley designed a smaller vitreous cutter with a diameter of 0.9mm (20gauge). This less invasive 3-port 20-gauge cannula-entry system is still used today.
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o
In 1990, de Juan and colleagues designed a variety of 25-gauge (0.5mm diameter)
vitreoretinal instruments for more delicate and precise surgical maneuvers.
o
Fuji et al designed a 25-gauge microcannular system and an array of 25-gauge
instruments referred to as transconjunctival sutureless vitrectomy system (TSV).

Trantas (1907) first coined the term Gonioscopy.

Salssmann (1914) was first to perform direct gonioscopy & is known as Father of
Gonioscopy.

―Goldmann‖ (1938) was first to introduce Gonioprism.


Recalls from previous papers

Rho kinase inhibitor-fausidil

Maximum tolerated dose of a new drug is evaluated in: PHASE 1

no.of vision centres under npcb ans.20000

ExPRESS glaucoma shunt is made up of stainless steel.

Ahmed glaucoma valve for children: FP8

Duration of light stimulus in HVF: 0.2 sec

High resolution pass Perimetry: P cells

Flicker Perimetry: M cells

Normative database not present in stratus OCT: ONH
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Dhaval Patel MD

High IOP may directly damage ganglion cell layer of retina.

Mucormycosis Rx Amphotericin B

Which is true- brimonidine decrease aqueous production

Brinzolamide: non-competitive and reversible

rhabdomyosarcoma marker- desmin

not a risk factor for rhegmat rd  hyperopia

orbit involvemnt in  b cell lymphoma

Ocriplasmin is a recombinant protease - vitreomacular adhesion

Tonometer with variation in application surface  Maklakov tonometer

Pigmentatory changes between posterior pole and equator [salt and paper retinopathy] are
seen in all of following except? Resolving retinal detachment, Rubella, Phenothiazine
toxicity, Fundus flavimaculatus  Fundus flavimaculatus

Which of the following procedure most commonly performed by eye surgeon at district level
 Phacoemulsification

Lacrimal gland supplied by  Greater petrosal nerve

A patient diagnosed with chalazion c/o pain. True statement is  chalazion is lipogranuloma

True about pterygium  resection via bare sclera technique cause recurrence of 30-70%

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