1. Common visual field defects have causes as follows:
DEFECT
CAUSE
Bitemporal hemianopia
Pituitary adenoma
Arcuate scotoma
Glaucoma (all types)
Central scotoma
Macular degeneration, optic neuritis
Homonymous hemianopia
Lesion in optic tract or stroke (clot) in
posterior cerebral artery
Ring scotoma
Retinal disorder (Retinitis pigmentosa)
2. SLE can cause:
- retinal vasculitis (exudates and hemorages),
- episcleritis
- conjunctivitis
- optic neuritis
- secondary Sjogrens syndrome
Rheumatoid arthritis can cause:
- scleritis and episcleritis
- scleritis can lead to eye performation (scleromalacia perforans)
- secondary Sjogrens syndrome
Behcet’s disease can cause:
- acute and recurrent anterior or posterior uveitis
- retinal vasculitis and vitritis
Reiter’s syndrome can cause:
- conjunctivitis
- uveitis
Juvenile chronic arthritis (AFP+) can cause:
- anterior uveitis
- cataract/glaucoma/macular degeneration occur more commonly
(chronic)
In addition:
IBD  anterior uveitis
Psoriatic arthritis  uveitis and conjunctivitis
Ankylosing spondylitis  uveitis
Sarcoidosis  recurrent/chronic granulomatous
anterior uveitis and “mutton-fat”
keratic precipitates in association
with granulomatous inflammation
3. Topical steroids have the following ocular effects:
- glaucoma (especially LOCAL administration) by
increased intraocular pressure
- cataracts (especially SYSTEMIC administration)
- exacerbation of infections (especially HSV)
4. Orbital cellulitis is usually associated with an infection in the paranasal air sinus. It
leads to conjunctivitis, eyelid swelling, proptosis and reduced ocular movement. It may
be accompanied by systemic indicators of infection like malaise or pyrexia. Causative
organisms are Haemophilus influenzae and Streptococcus pneumoniae and anaerobes. It
may be rapidly progressive and needs to be treated quickly to avoid visual loss, orbital
abscess formation and intracranial spread.
Cavernous sinus thrombosis (CST) is usually a late complication of an infection of the
central face or paranasal sinuses. Effective treatment of orbital cellulitis can reduce the
incidence of cavernous sinus thrombosis.
5. Painless loss of vision occurs with:
- retinal detachment
- retinal arterial occlusion
- retinal venous occlusion
- amaurosis fugax
- cataract
- arteritic and non-arteritic ischemic optic neuropathy
- open angle glaucoma
Keratitis tends to be painful and is caused by viral (HSV, VZV, adenovirus) or bacterial
(Staph aureus/epidermidis, Strep pneumoniae, enterobacter (E.coli, Proteus, Klebsiella),
Pseudomonas aeruginosa) or parasite (Acanthamoeba) infection.
6. Diabetic retinopathy is categorized into three grades:
Background
Microaneurysms
Dot-blot hemorrages
Edema and exudates
Preproliferative
Cotton wool spots
Venous beading, loops
Proliferative
Neovascularization at disc (NVD) and elsewhere (NVE)
The seriousness increases as we go from background to pre-proliferative to
proliferative, as do the likelihood of advanced disease complications (see below).
The macula can also be affected by edema, microaneurysms, exudates and
hemorages and thus is called diabetic maculopathy.
In advanced disease, complications include:
- iris rubeosis (new vessels in iris- can cause vascular glaucoma)
- vitreous hemorage
- retinal detachment
Retinal changes occur in types 1 and 2 diabetics.
7. The uveal tract includes the ciliary body, iris and choroids. It is present at birth. The
ciliary body produces aqueous humor for the anterior chamber, and drains the fluid via
the trabecular meshwork and the Canal of Schlemm. Ankylosing spondylitis causes
anterior uveitis, as do all other seronegative arthropathies. Carbonic anhydrase is found in
the ciliary body, where aqueous humor is made. Inhibition of carbonic anhydrase can be
used to decrease secretion of aqueous humor. This is a common therapy in glaucoma
(acetazolamide).
8. Amblyopia, defined as poor vision due to abnormal visual experience early in life
(before 9), affects approximately 3% of the population and carries a projected lifetime
risk of visual loss of at least 1.2 per cent.
Amblyopia is the impairment of vision without detectable organic lesion of the eye. The
most common cause is strabismus (squint), but other causes include:
- alcohol
- arsenic
- nutritional deficiency
- quinine
- reflex (results from peripheral irritation) - trauma
- tobacco (caused by ingestion)
- uremic
If strabismus develops in the sensitive period (up to 7-8) the brain responds by refusing to
see the image from deviating eye. This prevents diplopia but also causes lazy eye to form.
It is usually treated by:
- correcting refractive error (glasses)
- reversing amblyopia (occlude good eye, forcing amblyopic eye
to fix and see)
- Orthoptic management
- Surgery
Amblyopia is usually painless.
9. Palsy of CNIII leads to divergence (looking “down and out”), ptosis and pupil dilation.
Third nerve palsies are separated into “medical” and “surgical” causes. Since
pupillomotor fibers in CNIII have a difference blood supply from the rest of the nerve,
microvascular disorders like diabetes usually cause papillary sparing. Surgical causes,
like aneurysm of posterior communicating artery, DO involve the pupil.
Oculomotor nerve palsies may be congenital, as both unilateral and bilateral congenital
oculomotor nerve palsies have been decribed, alone AND in conjunction with other
neurological abnormalities.
Pilocarpine is a parasympathetico-mimetic, causing contraction of ciliary muscle and
constrictor pupillae. A palsy would have the opposite effect, given the CNIII has
parasympathetic outflow from the cilary ganglion.
10. Errors in refraction require correction. Hypermetropia involves the image being
focused behind the eye. A convex lens is used to focus the image onto the back of the
eye. It is caused by an abnormally small eyeball or a lens that can’t sufficiently focus.
It can be complicated by acute glaucoma (have to overconverge to focus on eye-ball,
bringing lens more spherical making posterior attachment to iris more likely).
Myopia involves the image being focused in front of the eye. A concave lens is used to
focus the image onto the back of the eye. It is caused by an abnormally large eyeball.
High myopia predisposes to retinal detachment, glaucoma (open angle as ciliary body
drainage insufficient), cataracts, chorioretinal atrophy and macular choroidal
neovascularization.
It is generally agreed that both myopia and hypermetropia are congenital and unalterable
except by glasses or surgery. In childhood, esotropia (convergent squint) is often a result
of hypermetropia (child overconverges as they focus on near objects). Exotropia is often
the result of myopia (child stares into distance).
11. Temporal giant cell arteritis is an arterial ischemic optic neuropathy. It causes scalp
tenderness (pain?) with inflammatory swelling of temporal arteries, jaw claudication and
elevated ESR and CRP. There is an RAPD (relative afferent pupil defect) and swollen
optic disc (hemorage and cotton wool spots) with altitudinal field loss. Systemic steroids
must be given for several years to prevent relapse.
It is most common in elderly.
NON-arteritic ischemic optic neuropathiy has no sign of inflammation and is associated
with atherosclerosis, hypertension, smoking and diabetes.
12. Corneal abrasions cause pain and watering, and blurred vision. Corneal abrasions are
demonstrated with flourescein drops and blue light-dye pools green in defect. Trauma,
UV light can cause. Conventional treatment consists of chloramphenicol with cyclopegic
(cyclopentolate 1% or homatropine 2%) for comfort, occlusive padding for a day,
followed by 4 times a day chloramphenicol ointment for 4-7 days. They usually heal by
themselves with this treatment, unless a foreign body is present or infection persists.
13. The normal pupil is slightly nasal to the center of the cornea. It’s size is determined
by a balance of the sphincter muscle and the dilator muscle. The dilator muscle is
innervated by the sympathetic trunk. The postganglionic fibres arise from the superior
cervical ganglion and the neurotransmitter is noradrenaline.
The sphincter muscle is innervated by the parasympathetic system via the
oculomotor nerve (CN III) through the Edinger Westphal nucleus.
Horner’s syndrome causes abruption of sympathetic outflow and thus inhibits dilation
(and thus constricts affected pupil).
A palsy of the oculomotor nerve causes paralysis of the sphincter which causes dilation.
Pilocarpine is a parasympatheticomimetic and thus increases sphincter muscle activity.
Glaucoma causes iris ischemia which causes it to be week and unreactive. An oval
enlarged and unreactive pupil results.
Optic neuritis causes a relative afferent papillary defect.
14. Retrobulbar neuritis is a type of optic neuritis between the eye and the brain. It’s
symptoms are similar to optic neuritis:
- blurred or dimmed vision
- central scotoma
- pain with eye movement
- eye tender to touch or pressure
- complete blindness in affected eye
Chronic open angle glaucoma is painless. However, acute closed angle glaucoma is
painful.
Iridocyclitis (acute) also known as anterior uveitis, is painful. It can be caused by HSV,
VZV, Fuchs cyclitis, trauma and systemic causes (Ankylosing spondylitis, Reiters,
Behcets, sarcoidosis, IBD, Psoriasis, Juvenile chronic arthritis).
Central retinal vein and central retinal artery occlusions are both painless.
Corneal erosion is painful. Symptoms include:
- severe pain (especially after awakening)
- blurred vision
- foreign body sensation
- dryness and irritation
- tearing, redness and photophobia
15. Herpes simplex can cause:
- superficial keratitis (heals without scarring)
- deep keratitis (heals WITH scarring)
- anterior uveitis (iris, ciliary body)
- dendritic ulcers (so called because of branching pattern)
It is often recurrent and needs treatment from topical acyclovir. Topical steroids
exacerbate this condition, turning a corneal ulcer into an amoeboid ulcer.
16. Opthalmic herpes zoster:
Primary infection conjunctivitis + dendritic ulcer
Secondary infection ANY ocular or ajoining (adnexal) structures
Dermatomal skin rash
Conjunctivitis, keratitis, anterior uveitis COMMON
Scleritis and episcleritis MAY occur
Herpes zoster may be associated with post-herpetic neuralgia.
17. Ptosis is a drooping of the upper eyelid. It can be caused by:
- Horner’s Sympathetic nerve palsy. Since Muller’s muscle is supplied
by sympathetic system, a ptosis arises.
Other symptoms include constricted pupil and anhydrosis
- Age-related
- trauma
- myasthenia gravis (presumably cause of fatigue of levator palpebrae)
- CN III nerve palsy (dilated pupil, “down and out“ eye) occurs As a result
of levator palpebrae being supplied by CN III.
** CN7 does NOT cause ptosis as it supplies orbicularis oculi which CLOSES the
eyelids.
18. Diplopia also known as double vision, can be caused by:
- incomitant squint: - neurological: - paralysis of CN III, IV or VI
- CNS disease (ophthalmoplegia)
- muscular: - myasthenia gravis
- mechanical restriction:
- thyroid eye disease
- orbital wall fracture
- orbital tumor
- “pseudotumor”
- surgical overcorrection of squint
- decompensation of latent squint
- spectacle problems
Monocular diplopia:
- disorders of the cornea or lens:
- keratoconus
- cataract
- lens dislocation
19. Uveitis can be caused by: - viruses (HSV, VZV, adenovirus)
- trauma
- Fuchs heterochromic cyclitis (heterochromia [color diff
between two iris], fine keratic precipitates (KPs)),
leading to glaucoma and cataracts.
- Systemic (IBD, TB, sarcoidosis, JIA, Behcets, Reiters,
ankylosing spondylitis, Psoriasis)
20. Commonly used drugs with ocular complications include:
DRUG
Ocular complication
Amiodarone
Verticillata (vortex pattern on
cornea)
Lens opacities
Ant. Ischemic optic neuropathy
Gold, chlorpromazine
Pigmented inclusions in
conjunctiva/lids
Antihistamines/B-blockers
TCA, anxiolytics
Dry eyes
Chloroquine/chlorpromazine,
Gold, NSAIDs, steroids
amiodarone
Lenticular deposits/keratopathy
Sulphonamides, metronidazole
Thiazides, Acetazolamide
Refractive error
Ethambutol, isoniazid
Reduced acuity, visual field defects,
color vision disturbance
Chloramphenicol
Optic neuritis/retrobulbar neuritis
Isotretinoin/sulphonamides,
salicylates Antineoplastic agent
Conjunctivitis/blepharitis
Ethambutol
Optic neuritis
21. Viral conjunctivitis is commonly caused by Adenovirus and herpes virus. Discharge
is watery, but nightime discharge causes stickiness in the conjunctiva. Follicles
representing grains of rice are seen (bacterial=papillae/”velvet” while
virus=follicle/”rice”). Corneal erosion is common and corneal ulceration should be
excluded. Secondary iritis can also occur. Pre-auricular lymph node involvement is
common. Swelling can expand to the ear.
Viral infection usually settles without treatment within two weeks. Topical agents
like acyclovir are effective against HSV. Symptoms can be aided by
vasoconstrictor/antihistamine combinations.
22. Atropine blocks parasympathetic activity and thus causes dilation
Morphine use causes pin-point pupils
Pilocarpine is a parasympatheticomimetic pupil constriction
CN VII and CN VI have no effect on pupils
23. Congenital nasolacrimal duct blockage presents with recurrent mucocele, noninfected swelling of the lacrimal sac or to lacrimal gland infection (dacrocystitis). Is
usually resolves itself but if it doesn’t, can be cured by probing at 9 months.
ACQUIRED forms of nasolacrimal duct obstruction can be treated with a bypass
(dacrocystorhinostomy).
Congenital forms arise because of abherrant development of the first pharyngeal arch,
and is not associated with a specific genetic inheritance.
24. Dysthyroid disease: infiltration of the orbital tissues and extraocular muscles by
edema and inflammatory cells cause: - proptosis, diplopia and muscle weakness
Other symptoms include:
- lid retraction and lid lag
- exophthalmos
- optic nerve compression
Proptosis can be unilateral or bilateral
Strabismus is usually horizontal
Exposure of the cornea can cause inflammation (exposure keratitis)
25. Rheumatoid arthritis tends NOT to cause anterior uveitis. It DOES cause scleritis and
episcleritis.
While viral conjunctivitis may cause anterior uveitis, it is usually adenovirus and
not HSV that is the causative agent.
26. Retinoblastoma is the most common primary malignant intraocular tumor to affect
children (1 in 20,000). Age of onset is 18 months and family history occurs in about 6%
in autosomal dominant fashion (Chr 13). Hereditary forms may cause bilateral
retinoblastomas. Leukocoria is usually the presenting sign. Retinoblastoma can cause
strabismus and secondary glaucoma.
Retinoblastoma’s are treated by enucleation (removal of eye) or by
radiotherapy/chemotherapy in small lesions. Prognosis is determined by the optic nerve
invasion. Survival is 90% at 3 years.
27. Oculomotor nerve palsies may be caused by aneurysm of the posterior
communicating cerebral artery. This is considered a neurosurgical emergency.
Oculomotor nerve supplied levator palpebrae and thus a palsy can result in ptosis.
Palsy causes the eye to look “down and out.”
Palsy can be caused by microvascular disease; this is considered a “medical”
palsy as it can be caused by hypertension, diabetes, etc. This type of CN III palsy is
associated with papillary sparing.
CN III carries parasympathetic innervation to sphincter pupillae; a palsy would
cause dilation (mydriasis).
28. The chief cause of optic neuritis is demyelination. Less commonly, viral infections,
vasculitis (SLE) or drugs (esp ethambutol) can cause. Clinically, it presents with rapidly
progressive loss of vision (central scotoma) in one eye with pain on eye movement. On
examination,
- central scotoma
- relative afferent papillary defect
Atypically, the other eye may become involved.
Recovery usually occurs spontaneously after few weeks, even without treatment.
At 5 years, the risk of developing MS is 60%.
Visual evoked responses are often abnormal. VERs can be used to evaluate optic nerve
damage, even in asymptomatic patients.
29. Hypermetropia predisposes to glaucoma (acute angle) because of overcompensation
near response. Retinal detachment occurs as a complication in HyPOmetropia (near
sighted), as does glaucoma, cataracts, choroidoretinal atrophy and macular choiroidal
neovascularization.
Abnormal development of the anterior chamber angle is the usual cause of congenital
glaucoma. The presenting sign is USUALLY buphthalmos, since the infant eyeball can
enlarge enormously with increased intraocular pressure. The three classic signs are
photophobia, epiphora (tearing) and blepharospasm (eyelid spasm).
Tears contain secretory IgA antibodies.
Most disease processes of the optic nerve cause early change in visual acuity, but
papilloedema causes LATE loss of acuity. Blurring is more common in the early stages.
The cornea is composed of three layers, from outside to inside, the epithelium, the stroma
and the endothelium. Epithelium can regenerate but involvement of the stroma or
endothelium in corneal disease causes scarring. Corneal guttata (age-related) and Fuchs
endothelial dystrophy (progressive) represent two processes that cause corneal
endothelial cell loss. Decompensation can lead to edema, loss of transparency and loss of
vision.
30. Rubeosis iridis is the neovascularization of the iris, leading to occlusion of the
anterior chamber angle and predisposing to glaucoma. Causes may include:
- diabetic retinopathy
- central retinal vein occlusion
- retinal artery occlusion
- radiation retinopathy
- sickle cell retinopathy
- chronic uveitis
- chronic retinal detachment
Laser photocoagulation to the central retina can improve rubeosis iridis. The central
retina is where neovascularization mostly takes place (macular area).
31. Leukocoria can be caused by:
- retinoblastoma
- cataracts
- toxocara granuloma
- advanced retinopathy of prematurity
- vitreous maldevelopment - retinal dysplasias
- corneal opacity
32. Binocular vision is vision in which both eyes are used together. The word binocular
comes from two Latin roots, bin for two, and oculus for eye. Having two eyes confers at
least four advantages over having one. First, it gives a creature a spare eye in case one is
damaged. Second, it gives a wider field of view. For example, a human has a horizontal
field of view with one eye of about 150 degrees and with two eyes of about 180 degrees.
Third, it gives binocular summation in which the ability to detect faint objects is
enhanced (improved acuity). Fourth it can give stereopsis in which parallax provided by
the two eyes' different positions on the head give precise depth perception. Such
binocular vision is usually accompanied by singleness of vision or binocular fusion, in
which a single image is seen despite each eye's having its own image of any object.
The optic disc is the area of blind spot. It has no neuroreceptors in one eye but the other
eye is sensitive and thus binocular vision can compensate for the blind spot.
33. Primary open angle glaucoma presents with increased intraocular pressure, optic disc
cupping and peripheral visual field loss. Headache, eye pain and visual acuity problems
do NOT occur.
A cup:disc ratio of 0.6 in one eye, or a difference of 0.2 between eyes, is
suggestive of glaucoma. An increasing cup: disc ratio is indicative of progressive disease.
Average cup:disc ratio is under 0.4. The normal optic disc has nerve fibers (pink because
of vascular perfusion), an area without nerve fibers (WHITE optic disc cup). As nerve
fibers are lost or damaged, proportion of pink rim diminished and the cup enlarges.
The blind spot corresponds to the area in front of the optic nerve head, where no
photoreceptors are present. Since glaucoma causes death of nerve fibers, this area would
(in theory) actually get smaller (it doesn’t though. It stays pretty much the same size
cause there still aren’t any photoreceptors over the area replacing the dead nerve fibers).
34. Diabetes causes: - diabetic retinopathy (background, preproliferative, proliferative).
- maculopathy
- cataracts
- glaucoma (primary open angle)
- vitreous hemorrage and tractional retinal detachment
- microvascular disease  CN palsies (esp. CN III) strabismus
This is a PARALYTIC squint
Non-paralytic squints are caused by persistence of childhood
squint or local muscle imbalance
35. The cornea and sclera form the outer wall of the eyeball. The cornea consists of a
stroma sandwiched between a multilayered epithelium and an inner monolayer of
endothelial cells. The stroma is 90% of the thickness, composed of collagen and
extracellular matrix. There are few cells and no blood vessels.
The cornea is avascular; its nutrition comes from diffusion from blood vessels at
limbus, from aqueous humor and from tear film.
The cornea is transparent because of the specialized arrangement of collagen
fibrils in the stroma, kept in a state of dehydration. Dehydration is accomplished by the
endothelium, which pumps ions from stroma into anterior chamber.
While epithelial cells can regenerate, endothelial cells can NOT, so when
endothelial cells are lost, the ability to pump ions and keep stroma dehydrated is lost, and
thus corneal opacities occur, called corneal decompensation or bullous keratopathy.
Normal aging, Fuchs heterochromic dystrophy and cataract surgery can all cause
endothelial cell loss.
36. Cataracts can be caused by:
Ocular factors
Blunt or perforating trauma
High myopia
Recurrent uveitis
Topical steroid use
Ionising radiation
Excessive UV exposure
IR irradiation
Systemic factors:
Diabetes
Steroid therapy
Atopy
Galactosemia
HyPOcalcemia
Dystrophia myotonica
37. Strabismus in a one year old is most commonly caused by hypermetropia. Other
causes (less common) include myasthenia, myopathy, nerve palsies, cerebral palsy,
hydrocephalus, any other cause of central or peripheral neurological deficit (including
intracranial tumor and retinoblastoma).
38. The commonest adult intraocular tumor is the choroidal melanoma, a malignant
melanoma of the choroids.
39. Enucleation is the closest parallel to traumatic loss of an eye. With that in mind, the
complications of an enucleation procedude include:
- loss of depth perception (stereoscopic vision)
- loss of part of visual field to the side of the eye lost, when looking straight
ahead. The loss is from about 180 to 150 degrees.
Visual acuity in the remaining eye is maintained. The pupil reacts the same except
consensual reflex is obviously absent (cause the eye is gone…).
40. Amblyopia is a defect in visual acuity not caused by organic disease, that occurs in
the sensitive period of eye development (before age 8). Common causes include:
- cataracts (sensory deprivation leads to lazy eye)
- strabismus
- central or peripheral CNS disorders affecting CN III, IV or VI can lead to
strabismus and thus amblyopia
- birth trauma, illness and family history, maternal infection
- anisometropia (refractive power of one eye differs from the other). Since
refractive errors commonly present with amblyopia
(hypermetropiaconvergent and myopia divergent)
Since maturity onset diabetes doesn’t (generally) occur before age 8, it can not
cause amblyopia.
41.