Presentation is loading. Please wait.

Presentation is loading. Please wait.

Ocular Anatomy G. Wollstein, MD Associate Professor.

Similar presentations


Presentation on theme: "Ocular Anatomy G. Wollstein, MD Associate Professor."— Presentation transcript:

1 Ocular Anatomy G. Wollstein, MD Associate Professor

2

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 – 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 -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

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/mm 2 -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 len s

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 -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

41 Extraocular Muscles

42 Orbit

43 Orbital base

44 Arterial Supply

45 Venous Drainage

46 Orbital Cranial Nerves

47 The End


Download ppt "Ocular Anatomy G. Wollstein, MD Associate Professor."

Similar presentations


Ads by Google