Eye cornea structure
The eye cornea structure will be interesting for those who want to understand the principle and conduct of Excimer-laser correction and those who is considering a corneal surgery.
![Eye cornea structure]( "Eye cornea structure")
Epithelial layer is a surface protective layer, it can restore itself when damaged. Since the cornea is a nonvascular tissue, it is epithelium which is responsible for oxygen supply, it is seized from the tear film. Epithelium is also in charge of liquids entering the eye.
Bowman’s membrane is located right beneath the epithelium and is responsible for protection and nourishment of the cornea. When damaged it is not regenerated
Stroma is the biggest part of the cornea. It mainly consists of collagen fibers arranged in horizontal layers. It also contains cells responsible for regeneration.
Descemet’s membrane separates stroma from endothelium. It is very elastic and can withstand damage.
Endothelium is responsible for corneal transparency and is involved in corneal nourishment. It is extremely slow in regeneration. Plays a very important role of “an active pump” discharging excess liquids from the cornea (otherwise the corneal will swell). This is how the endothelium maintains corneal transparency. Number of endothelial cells gradually decreases with age: from 3500/mm2 at birth to 1500-2000/mm2 at senior age. Density decrease happens due to deceases, injuries, surgeries, etc. When density drops below 800 cells/mm2, the cornea goes edematic and looses transparency.
The tear film on the epithelial surface is often called the sixth corneal layer, it also plays an important role in eye optical properties.
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