Maj Dr Rishi Pokhrel
Dept of Anatomy, NAIHS
• Peripheral organ of vision
• Present in anterior part of orbit
• 1 inch in diameter
• Orbital fascia and bulbar fascia
Orbital fascia and bulbar fascia
FASCIA BULBI (Tenon's capsule)
• It is a thin membrane which envelops eyeball from optic nerve to ciliary region;
• allows eyeball to move freely
• smooth inner surface pierced by vessels and nerves
• fuses with sheath of optic nerve and sclera
• lower part of membrane thickens into suspensory ligament (checks ligaments) which attaches to zygomatic arch and lacrimal bones.
Structure• Outer fibrous coat
is composed of– Sclera
• Middle vascular coat comprises– Choroid
– Ciliary body
• Inner nervous coat consists of– Retina
CORNEA• half inch wide convex and
• 5 layered
• Anterior chamber separates it from iris.
• avascular, nourished by lymph and aqueous humor
• rich nerve supply.
• Its junction with sclera is limbus.
• This visible white part of the eye is covered with conjunctiva.
• made up of dense fibrous tissue.
• It provides attachments to tendons of recti and obliqui.
• It is pierces by numerous nerves and vessels.
• It lines sclera and
separates it from
• consists of pigmented
tissue containing nerve
plexuses, network of
capillaries, arteries and
• connects choroid with iris.
• made up of ciliary processes (internally) and ciliary muscle (externally).
• muscular ring placed deep to anterior part of sclera.
• made up of radial and circular fibres.
• brought into action during accommodation e.g. it slackens suspensory ligament of lens thus making it move convex as is required for near vision.
IRIS• placed b/w lens and
• circular, colored and contractile curtain.
• central aperture – pupil
• made up of smooth muscle called sphincter pupillae and dilator pupillae.
• Decrees and increase the size of pupil - aperture
RETINA• Light sensitive layer
• 10 layers
• Cells - Rods and cones
• two components.– Pigmented layer (external layer) is attached to
choroid and continues over ciliary body to iris.
– Retina proper (internal layer) is in contact with vitreous. Ora serrata divides it into posterior optic part and anterior ciliary part.
• Ora serrata - wavy border behind the ciliary body.
• Macula lutea- at posterior pole of eyeball on retinal is a small yellowish spot.
– It presents fovea centralis - cones
• Optic disc – point where optic nerve
fibers converge to leave eyeball.
– 1 mm below and 3 mm medial to posterior pole.
– Its circumference is raised while its centre is depressed called optic cup.
– The disc is the blind spot of eye as it lacks nervous elements.
• transparent and circular, b/w vitreous and iris
• Biconvex, 10 mm in diameter and 4 mm thick.
• Ciliary muscle contraction -> slackening of suspensory ligament -> thickening of lens -> near vision
• ANTERIOR CHAMBER
• It is the space between cornea anteriorly & iris and central part of lens posteriorly
• POSTERIOR CHAMBER
• It is behind iris and suspensory ligament and adjoining part of lens posteriorly. The two chambers communicate through pupil; filled with a clear fluid called aqueous humor.
• VITREOUS HUMOUR (Vitreous body)
• transparent and jelly like substance that fills posterior 4/5 of eyeball.
• enclosed in a transparent membrane (hyaloid membrane)
• progressive condition of lens characterized by loss of transparency.
• a gray-white opacity in the lens.
• Congenital cataracts are usually hereditary but may be caused by viral infection during first trimester of gestation.
• Senile cataracts are uncomplicated cataracts of old age. Vision is lost if cataracts are not treated.
Retinal detachment• separation of retina
• The retina does not contain sensory nerves; thus condition is painless.
• D begins at the thin peripheral edge of retina and extends gradually beneath thicker central areas.
• is not checked it results in blindness.
Corneal grafting (keratoplasty)
• This surgical procedure of transplantation of cornea is performed to improve vision in corneal scarring, distortion or perforation.
• elevated intraocular pressure because of obstruction of outflow of aqueous humour. Glaucoma may be:
– Acute (narrow angle)
– Chronic (wide angle) glaucoma
• protective mechanism for eye where eyelids close when cornea is touched.
• mediated by ophthalmic division of 5th cranial nerve (sensory) and 7th cranial nerve (motor).
• This reflex may be used as a test of integrity of those nerves.
Substantia propria (Stroma)
Post Epithelium / Endothelium
Layers of Cornea
• Vascular layer
• 3 Parts
– Ciliary body
• Neural Photoreceptor layer
– Optic vesicle - cup
– Outer layer- Pigment
– Inner layer- Neural
Layers• Ten layers– Outside in
– Retinal Pigment epithelium
– Outer segment & Inner segment - Photoreceptors
– External Limiting membrane
– Outer Nuclear
– Outer Plexiform
– Inner Nuclear
– Inner Plexiform
– Ganglion cell
– Optic nerve fibre
– Internal Limiting membrane
• Mnemonic: Please Reply MY New Post, Never Pray God
– NB- Outside in- ? Dir light/Impulse
Layers Of The Retina
1. Retina contains photosensitive cells.
The outer limit of the retina is the Pigmented Epithelium (PEp)
1. Choroid (Ch) is a highly vascular layer containing melanocytes and
separated from the retina by the epithelial basement membrane
3. Sclera (S) consists of dense fibroelastic connective tissue
3 Coats Of The Eye