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.

Diseases and disorders