Dr. Puneet kumar Srivastava

Orbit Appendages of eyeball (Peri-ocular structures ) Lacrimal apparatus Eyebrows Eyelids Eyelashes Conjunctiva

ORBIT 1.The two bony orbits are quandragular truncated pyramids 2.Each orbit is formed by seven bones (Frontal/Ethmoid/Lacrimal/Palatine/Maxilla/Zygomatic/ Sphenoid) 3.Each orbit contains ( eyeball / muscles(6) / fat / vessels /nerves)

LACRIMAL APPARATUS Lacrimal Gland Lacrimal Passages 1. Punctum 2. Canaliculi 3. Common canaliculi 4. Lacrimal Sac 5. Nasolacrimal Duct

Eyelids/ Eyebrows /Eyelashes 6 Layers 1.Skin 2. Sub-cuteneous 3.Orbicularis occuli 4.Sub-muscular 5.Tarsal plate +LPS 6.Conjunctiva Glands 1. Mebomian 2. Zeis & Moll

Conjunctiva PARTS: PALPEBRAL ( Marginal /Tarsal /Orbital) BULBAR FORNICES Layers (3) 1.Epithelium/2.Adenoid layer/3.Fibrous layer Glands : Goblets cells(secrete mucin)

EYE BALL SHAPE : Ablate spheroid Dimensions: AP dia. =24mm Volume- 6.5ml Weight – 7gms Contents Coats Chambers Lens & Vitreous

COATS OF EYEBALL Fibrous coat: ant one-sixth Cornea Posterior five-sixth opaque-Sclera. o Junction of cornea and sclera- LIMBUS Vascular coat: Iris, Ciliary body and Choroid Nervous coat: Retina

CHAMBERS Anterior chamber: Between Cornea & Iris Depth is 3mm (range 2.5-4mm).25ml of aqueous humour. Posterior chamber: Triangular space between Iris & Lens Contains 0.06ml of aqueous humour.

Vitreous Transparent/Colourless,/Avascular Boundaries Ant : Lens & Ciliary body Posteriorly : Retina o Volume : 4cc ( 80% of Vol of eye ) o Weight : 4g ( 80% of Wt.of eye ) o Composition : 99% water 1%rest Provides : Optical medium ; Structural integrety

CORNEA Transparent avascular watch glass like structure forms 1/6 th of the outer fibrous coat Dimensions : Hori – 11.5 mm / verti – 11 mm Thickness : Centre-0.5mm / Peri – 1 mm Diopteric power – 45 D Layers (5) 1.Epithelium/2.Bowman’s membrane/3.Stroma 4.Descement’s membrane/5. Endothelium

SCLERA post 5/6 th of fibrous coat & covered by TENON’S CAPSULE. Its ant 1/3 rd is covered by bulbar conjunctiva. Inner surface contact- choroid Thickness of the sclera at the equator is 0.4to 0.6mm and adjacent to limbus is about 0.8mm Layers (3): EPISCLERAL/SCLERA PROPER/LAMINA FUSCA

UVEAL TRACT This constitutes middle vascular layer of the eyeball. 1.IRIS 2.CILILARY BODY 3.CHOROID

IRIS Anterior most, thin circular acts as a diaphargm In centre there is pupil which regulates the light Attachments-periphery to ant surface of the ciliary body. Iris divides into anterior and posterior chambers between cornea and lens.

CILILARY BODY Continuation of choroid at Ora serrata. Inner side – Divided into 2 parts 1.Pars plicata(2mm)(zonules) 2.Pars plana (4mm) Ciliary body consists of 5 layers: (1.Supra ciliary lamina/2.Stroma/3.pigmented epithelium/4.Non pigmented epithelium/5.Internal limiting membrane) Secretes - Aqueous

CHOROID Posterior most part of the vascular coat Extends from the optic disc to ora serrata Inner surface smooth brown and lies in contact with pigment epithelium of retina Outer surface rough lies in contact with the sclera. Layers: (3)- 1.Supra choroid lamina(lamina fusca)/2.Stroma/ 3.Layer of chorio cappillaries

LENS Transparent biconvex crystalline structure place between the iris and vitreous. Diameter mm Thickness - 5mm Weight mg Refractive power – D Structure : 1Capsule/ 2.Cortex/3.nucleus Suspended by Zonules/

RETINA Innermost tunic of the eyeball- transparent membrane. Thickness 0.56mm Colour -purplish-red / After death- white opaque. Extends from the optic disc to the ora serrata. Grossly: (3)-1.Optic disc/2.Macula /3.Peripheral retina.

MICROSCOPIC(10 layers) Choroid 1.Retinal pigment layer 2.Layer of rods and cones 3.External limiting membrane 4.Outer nuclear layer 5.Outer plexiform layer 6.Inner nuclear layer 7.Inner plexiform layer 8.Ganglion cell layer 9.Nerve fibre layer 10.Internal limiting membrane Vitreous

Blood Supply: Ophthalmic artery (ant. & post., long & short cilliary arteries) Cornea & Lens – Avascular Nerve Supply: Sensory- trigeminal (5 th ) C.N. Motor – 3(EOM(4)-SR,MR,IR,IO) / Sphinter pupil 4(SO)/ 6(LR) 7(Orbicularis oculi) Sympathetic- Dilator pupilae Lymphatic Drainage: Preauricular &Submandibular LN

VISUAL PATHWAY OPTIC NERVE | OPTIC CHIASMA | OPTIC TRACT | LAT GENICULATE BODY | OPTIC RADIATIONS This will ultimaltely end up in the visual cortex in the Occipital lobe.

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