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The cornea is the curved, transparent layer that covers the front part of the eye. Together with the lens, the cornea refracts light and consequently helps the eye to focus. However, whereas the curvature
of the lens can be adjusted to "tune" the focus, the curvature of the cornea is fixed.
Layers of the cornea
The cornea consists of five layers:
- Corneal epithelium: a thin epithelial layer of
fast-growing and easily regenerated cells. Tears keep this layer moist.
- Anterior limiting membrane (also Bowman's membrane): a tough layer that protects the cornea.
- Corneal stroma (also substantia propria); a thick, middle layer of transparent fibers
responsible for most of the focusing that the cornea performs. If the stroma is damaged, the cornea can lose its transparency, which can cause vision problems.
- Posterior limiting membrane (also Descemet's membrane): a thin acellular layer that serves
as the modified basement membrane of the corneal endothelium.
- Corneal
endothelium: a simple squamous or low cuboidal epithelium, an inner lining acting as a barrier to prevent water inside the eyeball from moving into and
hydrating the cornea, which leads to blurred vision.
See also:
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