5/12/2014
Embryology
Neural Ectoderm:
Brain,
Retina
Spinal Cord, Motor Neurons
and Ciliary Body
Mesoderm:
Muscle,
Connective Tissue, Bone, Cartilage, Blood Cells
Sclera, Episclera, Ciliary Muscle
Cornea,
CLINICAL OCULAR ANATOMY
AND PHYSIOLOGY
What is it and what does it do?
Course Overview
Orbit
Embryology
Ocular Anatomy &
Physiology:
Orbit
Lids
Conjunctiva
Lacrimal System
Tears
Extraocular Muscles (EOMS
Cornea
Sclera
Limbus
Function: Protect/House the globe
7 Bones
Palatine
Anterior Chamber
Uveal Tract
Lacrimal
Iris
Ciliary Body
Angle
Zygomatic
Maxillary
Lens
Vitreous
Retina
Cranial Nerves (II, III, IV, V, VI,
VII)
Ethmoid
Sphenoid
Frontal
http://classconnection.s3.amazonaws.com/33/flashcards/602033/jpg/bony_orbi
t_-_bones_(edit)1317453337237.jpg
Embryology
The eye is an extension of the Central Nervous
System (CNS)
Brain/Spinal
Orbit
Roof:
Lens,
Frontal & Sphenoid
Wall: Zygomatic, Sphenoid
Lateral
Cord
Superior
Surface Ectoderm:
Skin,
Regional bones:
Teeth, Sensory Receptors
Cornea, Lacrimal Gland, Conjunctiva
Floor:
Maxilla, Zygomatic, Palatine
Inferior
Orbital Fissure:
Infraorbital Artery, CN V2
Medial
Orbital Fissure:
CN III, IV, VI, V1, Superior Ophthalmic Vein
Wall: Maxilla, Lacrimal, Ethmoid, Sphenoid
Sinuses:
Sphenoidal,
Ethmoidal, Frontal, Maxillary
http://www.nature.com/nature/journal/v472/n7341/image
s/472042a-f1.2.jpg
1
5/12/2014
Lids
Lids
Function:
Eyebrow/Lashes
Function:
Protection
Protection
Tear
production/distribution
Tear drainage
Oil
secretion
Complications:
Stye (Hordeolum)
Chalazion (if chronic)
Glands:
Meibomian
(oil)
glands (sweat)
Accessory lacrimal glands (aqueous)
Ciliary
http://lasikblog.net/parts-of-an-eye-eyelid/
Lids
Lids
Layers:
Skin
Lacrimal System:
Gland:
Subcutaneous
layer
Duct:
Muscles
produces aqueous layer of tear film
drains tears
Upper
and lower lid
Complications:
Submuscular
areolar layer
Palpebral Conjunctiva
Insufficient
aqueous production – dry eye
drainage – excessive tearing
Canaliculitis – inflammation of tear duct
Inadequate
http://marineyes.com/images/Anatomy/Eyelidredeye12.jpg
http://upload.wikimedia.org/wikipedia/commons/c/cf/Gray896.png
Lids
Extraocular Muscles (EOMS)
Muscles: Striated
Orbicularis
Closes
Levator
Oculi (CN VII)
Function: ocular movement
Elevation,
Depression, Abduction, Adduction,
Cyclotorsion
Compilation:
eyelid
Palpebrae (CN III)
Elevates
Entrapment:
Ptosis
Paralysis:
eyelid
– paralysis of levator muscle
secondary to bone fracture (floor)
secondary to reduced innervation
“Drooping lid”
http://upload.wikimedia.org/wikipedia/commons/6/6f/Gray894.png
http://www.pfofflaserandeye.com/Extraocular%20m%20side.gif
2
5/12/2014
Ocular Components
Fibrous Outer Layer:
Cornea,
Conjunctiva
Thin tranlucent mucous membrane covering the
sclera and eyelids
Function:
Partitions:
Conjunctiva, Sclera
Vascular:
Choroid
Ciliary
Ensure
Body
Iris
Palpebral:
inner lid surface
covers the globe
Fornix: junction between the two
Neural Layer:
Bulbar:
Retina
Macula
Optic
smooth movement of lids over the globe
http://www.glaucoma.org/uploads/eye-anatomy-2012_650.gif
Nerve
http://www.stlukeseye.com/images/img-conjunctiva.jpg
Conjunctiva
Sclera
Dense connective tissue layer
Continuous with the corneal stroma and limbus
Function:
Allergies
Infections
Tissue
Protection
Complications:
modifications
http://www.conjunctivitis.co/wp-content/uploads/2011/12/AllergicConjunctivitis-Pictures-300x203.jpg
Limbus:
Corneo-scleral
Melanosis:
junction
increase in melanocytes within this region
http://en.wikipedia.org/wiki/Pinguecula
Sclera
Cornea
Principle refracting component of the eye
Avascular
Bulbar Conjunctiva:
Overlying
+40D (60%)
Neovascularization: Abnormal vessel growth
clear tissue layer
Complications:
2’ to oxygen deprivation
Layers:
Epithelium
Bowman’s Membrane
Stroma
Descemet’s Membrane
Endothelium
Scleritis
http://diseasespictures.com/scleritis/
http://i1.allaboutvision.com/i/conditions/cornea-layers-325x325.jpg
3
5/12/2014
Cornea
Cornea
Epithelium:
Cells
replaced every 7 days
Rapid healing
Corneal
Tight
Complications:
Keratoconus
Abrasions
Recurrent
Abrasions (24 hours)
Corneal Erosions
(RCE)
Junctions
Maintain
Ectasias
Trauma
Pellucid
Marginal
Degeneration
Neovascularization
barrier with external environment
CL
Complications:
overwear
hypersensitivity
Allergic
Keratitis
Endothelial
Fuch’s
Aging
Arcus
Cornea
Dense
fibrous sheet of collagen
Function:
Create
a smooth refracting surface
debris
Provide O2 to the cornea
Wound repair
Stroma:
Remove
of the corneal thickness
fibrous connective tissue
Clear media
Dense
Disarrangement
can lead to corneal haze
Cornea
Tear Film
Descemet’s Membrane:
Endothelial
Thickens
5-15
Liquid layer covering the corneal surface
Function:
Protection
provide rigidity and shape of cornea
90%
senilus
Tear Film
Bowman’s Membrane:
May
dysfuction
Dystrophy
basement membrane
over one’s lifetime
Layers
Aqueous
microns
Endothelium:
Lacrimal Gland
Accessory Lacrimal Glands
Inner
most corneal layer
“Leaky” barrier between the anterior chamber
Goblet Cells
Keeps the ocular surface moist
Mucin
Bulbar Conjunctiva
Helps spread tears
Lipid
Meibomian Gland
Slows tear evaporation
http://www.mydryeyes.com/Images/graph-01.jpg
4
5/12/2014
Tear Film
Uveal Tract
Complications
Lacrimal
Systemic
Cervical Ganglion
Constriction:
Cranial
parasympathetic (rest or digest)
Nerve III
cell loss
Deficient Dry Eye
Meibomian
sympathetic control (fight or flight)
Superior
Deficient Dry Eye
Goblet
Iris
Dilation:
Inflammatory Conditions
Sjogren’s Syndrome
Thyroid Eye Disease
Mucin
Lipid
Gland Dysfunction
Gland Dysfunction (MGD)
Imbalance of omega-3 and omega-6
http://what-when-how.com/wpcontent/uploads/2012/04/tmp361_thumb.jpg
Uveal Tract
Uveal Tract
Middle (vascular) layer of the eye
Complications
Iris
Trauma
Ciliary
Inflammation
Body
Choroid
Pigment
Dispersion Syndrome
Closure
Innervation Dysfunction
Angle
http://www.oculist.net/others/ebook/generalophthal/vaughan
/public/co_figures/ch007/ch7fg1.jpg
Uveal Tract
Iris
Diaphragm
Uveal Tract
controlling the amount of light entering the
eye (pupil)
Anterior to the lens
Color is determined by melanocytes concentration
Blue:
few melanocytes
many melanocytes
Green: combination of blue and brown
Brown:
Ciliary Body
Ring
2
shaped structure, where the iris inserts
Regions
Pars
Pars
Plicata
Aqueous production
Plana
Posterior region of the ciliary body
Continues into choroid and retina
Allows
aqueous to flow from posterior to anterior
chamber
5
5/12/2014
Uveal Tract
Lens
Ciliary Muscle
CN
III innervation
Controls accommodation
1/3
Aqueous Humor
intraocular pressure
lens and cornea
Removal of metabolic waste
Drains through the trabecular meshwork
Nourishes
Uveal Tract
23um
Paralysis:
Mydriatics
Muscle
Complications:
Subluxation
Spasm:
Cataract
Vossius
excess
Age
Glaucoma
Increased
per year
Trauma
(dilation drops)
Accommodative
Lens grows throughout life
Lens
Complications:
Muscle
of the refractive power of the eye
ultra violet light
Filter
Maintains
Avascular lens located just behind the iris
Function:
Ring
Related Cataracts
Nuclear
intraocular pressure
Cortical
Posterior Subcapsular
Presbyopia
Uveal Tract
Anterior Chamber
Vascular layer between the sclera and retina
Function:
Provides
nutrients to the outer retinal layers
Aqueous
Choriocapillaries
Waste
removal from the outer retina
Photoreceptors →
Absorb
RPE → Bruch’s membrane → Choroid
excess light not absorbed by the retina
Tapetum
Space between the posterior cornea and the
anterior iris
Houses the trabecular meshwork
lucidum (reflective layer found in some animals)
drainage structure
Corneoscleral meshwork
Uveal
meshwork
Some glaucoma drugs improve outflow
Brimonidine
Pilocarpine
Prostoglandins
6
5/12/2014
Anterior Chamber
Complications:
Angle
recession
glaucoma
Acute angle closure
Neovascular
Retina
Neural tissue located
interior to the choroid
Function:
Transform an optical image
into a neural signal
Layers:
Retinal Pigment Epithelium
Photoreceptor Layer
External Limiting
Membrane
Outer Nuclear Layer
Outer Plexiform Layer
Vitreous
Retinal Pigmented Epithelium
Function:
Homeostatis
of ionic micro-environment
outer retina
Break down cellular debris
Nourish
repository (waste and short term nutrients)
properties
Viscoelastic
Retina
Gel like structure occupying the posterior half of the
eye
Function:
Metabolic
Inner Nuclear Layer
Inner Plexiform Layer
Ganglion Cell Layer
Nerve Fiber Layer
Internal Limiting Membrane
Components:
Water
Collagen
Hyaluronic
Acid
Vitreous
Complications
Syneresis
Posterior
Vitreous Detachment
Astroid Hyalosis
Retina
Retinal Pigmented Epithelium
Complications
Retinitis
Pigmentosa
RPE failure to clear cellular debris
Results in photoreceptor cell death
Rods initially, cones in late stage
7
5/12/2014
Photoreceptor Layer
Rods and Cones located within this layer
Rods:
Make
Used
Outer Nuclear Layer
Houses the cell bodies of the Rods and Cones
22-55 um
up 95% of the photoreceptors
in dim light and for peripheral vision
Cones:
Makes
up 5% of the photoreceptors
acuity
Color Vision
High
L,
M, S cones
Photoreceptor Layer
Outer Plexiform Layer
Complications:
Age
related cell death
Age related macular degeneration
Accelerated cell death
Cone-Rod
Stargart’s
Houses the axon terminals of Rods/Cones
Function:
Synapses
Bipolar
with inner retinal layers
and horizontal cells
Dystrophy
Disease
Achromatopsia
Protanopia
Deuteranopia
Tritanopia
External Limiting Membrane
Not a true membrane
Composed of Muller cell processes
Inner Nuclear Layer
Houses the cell bodies of inner retinal cells
Horizontal
Cells
Cells
Bipolar Cells
Amacrine Cell
Muller
8
5/12/2014
Inner Plexiform Layer
Synapses between bipolar, amacrine, interplexiform
cells and ganglion cells
Macula
Depressed region of densely packed cone
photoreceptors
Highest visual acuity region in the retina
Avascular zone
Complications:
Macular
degeneration
Dystrophy
Cone-Rod
Ganglion Cell Layer
Houses cell bodies of ganglion cells
Optic Nerve
Ganglion cell accumulate and exit the eye eye
Lack of photoreceptors
Complications:
Physiological
blind spot
Glaucoma
Papilledema
Drusen
Staphylomas
Retina
Peripheral Retina
Nerve Fiber Layer
Unmyelinated
ganglion cell axons
Complications:
Glaucoma
Results
in thinning of nerve fiber layer
Internal Limiting Membrane
Basement
Everything outside of the posterior pole
Structurally less well developed
Complications
Neoplasms
Thinning/tearing
of the retina
membrane
9
5/12/2014
Retinal Circulation
Provides nutrients to the retina
Outer Retina: Choroid
Inner Retina: Central Retinal Artery
Cranial Nerve III
Midbrain
→ EOMS
Medial
Rectus
Inferior Rectus
Inferior Oblique
Hypertension
Diabetes
Retinopathy
Oculomotor Nerve – Inferior Division
Midbrain
of Prematurity
→ Ciliary Ganglion
Pupillary
Constriction
Accommodation
Cranial Nerves
12 Cranial Nerves
6 innervate orbital structures
Cranial Nerve III
Oculomotor Nerve – Superior Division
Midbrain
→ Superior Rectus Muscle
Elevation,
Midbrain
Eyelid
Cranial Nerve II
Optic Nerve
Composed
of retinal ganglion cells
Retina → Optic Nerve → Lateral Geniculate Body
Function: Sight
adduction, intorsion
→ Superior Levator Muscle
elevation
Cranial Nerve IV
Trochlear Nerve
Midbrain
→ Superior Oblique Muscle
Depression, abduction,
Intorsion
Complications
Highly
susceptible to traumatic paralysis
Syndrome
Brown’s
10
5/12/2014
Cranial Nerve VI
Abducens Nerve
Pons
→ Lateral Rectus Muscle
Abduction
Complications:
Duane
Syndrome
Cranial Nerve VII
Facial Nerve
Pons
→ Facial muscles
Facial
expressions
Closure
Lacrimal gland secretion
Lid
Complications
Bell’s
Palsy
The End
mvaldes@uiwtx.edu
11