The cornea is the transparent outer coat of the eye. It has 5 layers - epithelium, Bowman's membrane, stroma, Descemet's membrane, and endothelium. The stroma makes up around 90% of the corneal thickness and contains collagen fibrils and keratocytes. The cornea is avascular but receives nutrients from blood vessels in the surrounding tissues. It has sensory innervation from the trigeminal nerve but lacks blood vessels in its central region to maintain transparency.

1. DONE BY,
S. ARYA DAS,
1st yr 2nd SEM,
BACHELOR OF OPTOMETRY,
BHARTIMAIYA COLLEGE OF OPTOMETRY.

2. ANATOMY OF CORNEA

3. What is cornea?
Transparent,
Avascular, Watchglass
like
Forms anterior 1/6 th
of the outer fibrous
coat of eyeball

4. Dimensions
Anterior surface is elliptical
Horizontal diameter of 11.75mm and vertical diameter of 11mm
Posterior surface is circular and average diameter is 11.5mm
Centre thickness 0.52mm and peripheral 0.67mm
Ref power: Anterior= +48 D, Posterior= -5 D and Total= +43 D
Ref Index= 1.37

5. Layers of Cornea

7. 1. Epithelium

8. Squamous cells
Wing cells

9. i. Basal Layer
Tall, Columnar polygonal shaped, arranged in a palisade
like manner.
Basal cell has an oval shaped nucleus
Mitrochondria are small and depends on Pentose Shunt
for metabolism
Basal cells are lateral to other basal cells & anterior to
wing cells by desmosomes and maculae occludentes

11. ii. Wing Cells
Forms 2-3 layers of
polyhedral shaped cells
Nuclei are flat
Attached with basal cells
posteriorly and other wing
cells laterally and anteriorly.

12. iii. Flattened cells

13. SURFACE CELLS
WING CELLS

14. 2. Bowman’s membrane
Consists of acellular mass of condensed
collagen fibrils.
8-14 μm in thickness
It is not a true elastic membrane, simply
a condensed superficial part of stroma.
Once destroyed, it does not regenerate.

15. 3.Stroma

16. STROMAL LAMELLAE
Dense and orderly
fibrous connective
tissue.
They are made up of
stable proteinaceous
collagen fibrils
arranged parallel to
one another.
Regular arrangement
is important for
corneal transparency

17. Dimensions and arrangement

18. Keratocytes
The cells present in the lamella are
keratocytes.
Present between collagenous
lamellae.
Thin, flat cells
5-50 μm of intercellular space.

20. 4. Descemet’s membrane
10-12 μm-
THICKNESS
Structureles
s
Slightly
elastic
Secreted by
the
endotheluim
Very
regularly
arranged.

21. It represents the basement
membrane of the endothelium.
It is made up of collagen and
glycoprotein.
It is resistant to chemical agents,
trauma, infection and
pathological processes.
Posterior surface of Descement’s
membrane at periphery, shows
rounded Wart-like structure
called Hashel Henle bodies

22. HASHEL-HENLE WARTS

24. 5. Endothelium
Single layer of flat polygonal cells
Cell density in young adults= 2400-3000
cells/mm2
Endothelial cells are attached to the
descemet’s membrane by
hemidesmosomes

25. The desmosomal linkage is calcium
dependent and plays an important
role in maintaining the barrier
function of endothelium
The endothelium contains an active
pump mechanism, involved in
active secretion and protein
synthesis.
The endothelial cells contains the
higher number of mitochondria.

26. Thin Optic Section of the Human Cornea.
This image clearly demonstrates the stromal contribution to
total corneal thickness (i.e. 90%).

27. Blood supply of Cornea
Cornea is avascular
structure
Small loops derived
from the anterior
cilliary vessels invade its
peripheri for about 1
mm and provide
nourishment.
These loops are present
in subconjunctival
tissues which overlap
the cornea.

28. Nerve supply of Cornea
Cornea has rich
supply of sensory
nerve ending derived
from long ciliary
nerves (branch of
ophthalmic division
of trigeminal nerves).

29. REFERENCE
Anatomy and
physiology of
eye
Physiology
of eye
Internet