Cornea

The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber and provides most of an eye's optical power http://www.eyeglossary.net/#C. Together with the lens, the cornea refracts light and consequently helps the eye to focus. The cornea gives a larger contribution to the total refraction than the lens, but whereas the curvature of the lens can be adjusted to "tune" the focus, the curvature of the cornea is fixed.

Related Topics:
Eye - Iris - Pupil - Lens - Refracts - Focus - Curvature

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

The cornea has sensitive nerve endings; touch of the cornea causes an involuntary reflex to close the eyelid. Because transparency is of prime importance, the cornea does not have blood vessels; it receives nutrients via diffusion from the tear fluid at the outside and the aqueous humour at the inside. In humans, the cornea has a diameter of about 12 mm and a thickness of 0.5 - 0.7 mm in the center and 1.0 - 1.2 mm at the periphery.

Related Topics:
Nerve - Reflex - Eyelid - Blood vessel - Diffusion - Aqueous humour - Human - Mm

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Medical terms related to the cornea often start with "kerat-".

~ ~ ~ ~ ~ ~ ~ ~ ~ ~