Cornea
What is the Cornea
The cornea is the circular, transparent membrane that covers the pupil. Its curved shape makes it work like a strong lens, focussing onto the retina all the light that enters your eye. (The retina is the photographic ‘film' of the eye). The curvature is smoothly graded to give the highest quality focus to the light entering your eye, and is rounded in a similar way to a football.
To see well the cornea must be perfectly clear; if it is not transparent then the quality of sight will be reduced; if the opacification is marked there will be no useful sight.
Exposed to the air, the cornea needs to be constantly protected from damage from scratches, foreign bodies or infection. Damage to the cornea would lead to scaring and loss of sight and a set of defensive measures are present to protect it.
- It is bathed in tears which are refreshed every time you blink;
- It has more sensitivity to pain and touch than any other part of the body,
- Any slight touch of the surface produces a reflex closing of the eyelids and profuse watering.
- The tears also contain a natural antibiotic.
Internationally diseases of the cornea are common and a major cause of blindness. In the United Kingdom however, problems are less frequent but are important and may require specialist attention.
Common Diseases Of the Cornea
Corneal Graft (Penetrating Keratoplasty)
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