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