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G. Wollstein, MD Associate Professor

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1 G. Wollstein, MD Associate Professor
Ocular Anatomy G. Wollstein, MD Associate Professor


3 The eye Diameter: 24mm Anterior chamber: 3mm deep, volume of 250μL
Posterior chamber: 60μL Vitreous: 6.5mL Diameter: 24mm Anterior chamber: 3mm deep, volume of 250μL Posterior chamber: 60μL Vitreous: 6.5mL

4 Tear Film Superficial oily layer Aqueous layer Mucin layer
Made by Meibomian glands Function: anti-evaporative agent Aqueous layer Made by lacrimal and accessory lacrimal glands Function: provides smooth optical surface, nutrients, immunoglobulins, oxygen Mucin layer Made by goblet cell Function: wetting agent

5 Cornea Oval shape Varying thickness Limbus: 1mm
12 mm wide 11 mm high Varying thickness Center: 0.55mm Limbus: 1mm Radius of curvature: 8mm

6 Cornea Average power: 43 diopters
Steepest centrally, flatter peripherally More curved posteriorly then anteriorly

7 Corneal Layers Epithelium Bowman Stroma Descement Endothelium
Histology OCT Epithelium Bowman Stroma Descement Endothelium

8 Corneal Epithelium Constant turnover of cells
Stem cells located in crypts adjacent to limbus Move centripetally and anteriorly Anchored to basement membrane by hemidesmosomes

9 Bowman’s layer Anterior most stroma Thickness: 8-14μm
Randomly dispersed collagen fibrils Cannot regenerate [

10 Stroma Composition: Collagen fibers Ground substance Keratocytes

11 Stroma Fibrils arranged in oblique and parallel lamellae
Individual fibrils run the entire diameter of the cornea Spatial organization of the fibrils allows for transparency

12 Descemet’s Membrane Basement membrane of the corneal endothelium
Made of type IV collagen Thickens with age [

13 Corneal Endothelium A monolayer of hexagonal cells
Cell density: 3000 cells/mm2 Decreases with age Cannot regenerate Loss of cells results in corneal edema

14 Anterior Chamber Angle
Formed between the posterior aspect of the cornea and anterior aspect of iris Opening of the drainage system Trabecular meshwork Schlemm’s canal Collector channels Ant. ciliary v.

15 Uvea Iris Ciliary body Choroid

16 Iris Anterior border layer Stroma Dilator muscle
Posterior pigmented layer Two layers of heavily pigmented epithelial cells Melanin

17 Iris Innervation Dilator muscle: Primarily sympathetic autonomic system Sphincter muscle: Parasympathetic system

18 Ciliary Body Base inserts into the sclera spur via the longitudinal muscle fibers Gives rise to the iris Apex is bordered by the ora serrata of the retina

19 Ciliary Body - Functions
Accommodation Controlling the lens curvature through the zonules Aqueous humor formation Ciliary body epithelium Trabecular and uveoscleral outflow

20 Lens Diameter: 9-10mm Ant.-post. width: 6mm Power: 20 Diopters
Cornea: 40D The actively dividing lens epithelial cells are located just anterior to the equator of the lens

21 The high refractive index of the lens results from a high concentration of alpha, beta and gamma crystalins in lens fibers

22 Choroid Thickness: 0.25mm Highly vascularized layer
Fenestrated vessels Primary metabolic source for the RPE

23 Choroid “Spaghetti bowl”

24 Choroid - Vasculature Arterial supply: Long and short posterior ciliary a. and anterior ciliary a. Venous drainage: Channeled toward equator vortex veins -> ophthalmic v.

25 Bruch’s Membrane Separating between the choroid and retina
Created from the fusion of basement membranes of the choriocapillaris and RPE Play a critical role in preventing penetration of abnormal vasculature into the retina

26 Retina Converts light stimuli into electrical impulse
Clinical macula: Bounded by the vascular arcade Histological macula: >1 ganglion cell body

27 Retina Fovea: Avascular center of the macula “Center of vision”

28 Retina Multilevel connections between photoreceptors and optic nerve

29 RPE A monolayer of hexagonal cells
RPE cells in the macula are taller, thinner and contain more and larger melanosomes Functions include: Vitamin A metabolism Maintenance of the outer blood retina barrier Phagocytosis of the photoreceptor outer segments Absorption of light Heat exchange Formation of matrix around the photoreceptors Active transport of materials

30 Photoreceptors The outer segment consists of discs connected to the inner segment by the cilium Constant shedding of discs as exposed to light High concentration of mitochondria in the inner segment to provide the energy requirements

31 Photoreceptors Photoreceptor density is greater in the fovea than elsewhere in the retina The only layers of the retina present in the fovea are the photoreceptors and Henle’s layer (outer plexiform layer in the fovea)

32 Photoreceptors Nuclei in the outer nuclear layer
Axons (cone pedicle and rod spherule) in the outer plexiform layer

33 Inner Nuclear Layer Made up of the cell bodies of the bipolar, horizontal and amacrine cells Interconnect photoreceptors with each other and with ganglion cells Initial steps of image processing

34 Muller cells Extend from the internal to external limiting membranes
Nuclei in the inner nuclear layer Provide support and structural functions for the retina

35 Inner Retina Ganglion cell layer Inner plexiform layer
Cell bodies Inner plexiform layer Ganglion cells dendrites Nerve fiber layer Ganglion cell axons

36 Retina – Blood Supply CRA enter the eye through the optic nerve and bifurcate into 4 main branches Supply inner retina down to the inner nuclear layer Outer retina supplied by the choroidal vasculature

37 Cool picture!

38 Vitreous Constitutes 95% of the eye volume Main component: water (98%)
The component that make vitreous viscous is hyaluronic acid

39 No time to cover other important ocular and orbital structures
Assembly of other important slides follows

40 Eyelids Med and lat palpebral lig Levator palpebrae

41 Extraocular Muscles

42 Orbit

43 Orbital base

44 Arterial Supply

45 Venous Drainage

46 Orbital Cranial Nerves

47 The End

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