Anatomy of cornea

Presented by:- Prachee Shree

2nd sem, 1st year

B.optom

Instructor:- moutushi madam

What is CORNEA..?

Avscular tissueTransparentImportant OpticalElement (+43.27D)Very sensitive

Corneal Dimensions

HVID=11.7mmVVID=10.6mmArea=1.3 cm sq.Saggital depth=2.6mm(avg.)Refractive index=1.376Power :-anterior(+48D) :-posterior(-5D)Thickness: central- 0.52mm

peripheral- 0.67mmRadius of curvature:

anterior surface:-7.8mmposterior surface:-6.2-6.8mm

Corneal Dimensions

Corneal Composition• 78% water

• 15% collagen

• 5% other parts

• 1% GAGs

• Epithelium » 10% of cornea’s wet weight

Layers of CORNEA

Corneal EpitheliumBowman’s MembraneCorneal StromaDescemet’s MembraneCorneal Endothelium

Corneal EpitheliumOuter most layer50 microns thick3 types of cellCan regenerateProvides smooth surface

EPITHELIUM CELLS SURFACE CELLS (2 Layers)• Thin• Squamous• Overlapping polygonal cells

WING CELLS (2 Layers)• Overlays Basal layer• ‘Wings’ protruding into space between domes of

basal cells BASAL CELLS

• Deepest• Columnar• Hemispherical anterior surface

Bowman’s Membrane

Acellular12 microns thick (8-14µm)Thin, Elastic MembraneDoes not regenerate and is

replaced by Opaque Scar Tissue

Corneal Stroma0.50 µm thick Composed of Collagen fibreTough and Hard to puncture or

cut2-3 % Keratocytes and 1 % GAGs200-250 Lamellae superimposed

on one another

Descemet’s Membrane

10 microns thickHighly elastic AcellularProduced by EndotheliumCan regenerate if destroyed

Corneal Endothelium Innermost layer5 lakhs polygonal cellsReceives nutrients from Aqueous

HumourDegenerate & Die but can’t

regenerateMost important for corneal

transparency If damaged causes, Corneal

hydration & oedema occurs

Specular reflection

Supply to cornea

Blood supply

Supplied by conjunctival & episcleral capillary network in the limbal region

Trigeminal nerve

Ophthalmic division

Nasociliary nerve

Long ciliary nerve conjunctival nerve

Pericorneal plexus70-80 nerves innervates

Stromal plexus

Sub epithelial plexusLooses sheath of shwann

Supplies all over epithelial layers

Nerve supply

Functioning of cornea

Main refracting materialActs as protective layer

1

Any

queries…??????

?

1.Substantia propria is another name of which layer of cornea….?

2.Increase in size of corneal endothelial cells is called_______________.

questions for you

CONTD…

3. Any deformity in regular polygonality (shape) of corneal endothelial cell is said to be_________________.

4. Which corneal layer is absent in carnivores animal…?

Contd…

5. What is the main source of oxygen supply in cornea…?

Thank you for all

Best wishes for upcoming exams