1. HISTOLOGY OF CORNEA & RETINA

2. CORNEA

3. Corneal epithelium
(Anterior epithelium)
Bowman’s membrane
Corneal Stroma
Descement’s Membrane
Endothelium
(Posterior epithelium)

4. Corneal epithelium: Stratified squamous non keratinised epithelium
1mm thick
Highly sensitive
Irritation or injury causes pain,lacrimation,photophobia,blinking….

5. Bowman’s capsule: Also called anterior limiting membrane
10 to 12 micrometer.
Dense mass of collagen fibers
Acts barrier—spread of infection
Damaged—can’t regenerate

6. Corneal stroma: 90% thickness 200—230 sequentially arranged lamellae
Bundles of collagen fibers—highly ordered.
Transparent
Flattened fibroblasts are located b/w lamellae.

7. Posterior limiting membrane:
Also called Descemet’s membrane.
Acellular
Regarded has BM of endothelium

8. Endothelium:
Single layer of cuboidal cells.
Metabolic exchange….

9. Cornea Stratified squamous epithelium Bowman’s membrane
Substantia propria
Descemet’s membrane
Mesothelium
Corneal corposcles

10. RETINA Neural sensory layer. Inner coat—posterior 3/4th surface.
Specialized area—fovea centralis—only cones-most acute vision.
Also ‘blind spot’, ‘optic disc’….

11. LAYERS OF RETINA Pigment cell layer Layer of rods & cones
External limiting membrane
Outer nuclear layer
Outer plexiform layer
Inner nuclear layer
Inner plexiform layer
Ganglion cell layer
Nerve fiber layer
Internal limiting membrane

12. Pigment layer…. Lined by cuboidal epithelium
Cytoplasm contains melanin pigment.
Melanin pigment—absorbs light
Forms blood retinal barrier b/w retina and vascular system of choroid.

13. Functions:
absorption of light
Phagocytosis of tips of rods and cones
Structural and metabolic support
Storage, esterification and release of Vitamin A

14. Layer of rods and cones…
Rod and cone cells—photoreceptors
Tip of rods and cones are surrounded—processes of pigment cell layer.

15. External limiting membrane…
Junctional zone b/w Muller’s cells and photoreceptor processes

16. Outer nuclear layer…..
Consist of cell bodies and nuclei of rods and cones.
Darkly stained area
Cone cell---color vision in good lighting condition (Iodopsin)
Rod cell---sensitive to lower intensities of light.
(Rhodopsin)

17. Outer plexiform layer…
Consist of axons of rods & cones + dendrites of bipolar neurons + horizontal cells.

18. Inner nuclear layer….
Consist ----bipolar neurons + Amacrine cells +Muller’s cell + Horizontal cell

19. Inner plexiform layer; Consist of axons of bipolar + dendrites of ganglionic cells + displaced amacrine cells.

20. Ganglionic cell layer….
Consist body nuclei of large ganglion cell
Nerve fiber layer
Consist of axons of ganglion cell gather together and leave eye as OPTIC NERVE..

21. Internal limiting membrane…
Seperates retina from vitreous humour
Formed by union of terminal expansions of Muller cells and their BM…….

22. Other cells of Retina…..
Horizontal cells- association neurons , inhibitory interneurons , GABA
Amacrine cells –’no axons’
- modulate the photoreceptive signals
Muller’s cells – Glial cell
- Mechanical support
- stores glycogen

23. Retina Layer of rods and cones Outer nuclear layer
Outer plexiform layer
Inner nuclear layer
Inner plexiform layer
Ganglionic cell layer
Layer of optic nerve fibers