The cornea is the outer, clear, round structure that covers the colored part of the eye (iris) and the pupil. The cornea directs light rays into the eye and helps focus them on the light-sensitive retina at the back of the eye, providing sharp, clear vision.

Vision problems such as astigmatism or nearsightedness (myopia) are often caused by changes in the normal shape of the cornea.

By	Healthwise Staff
Primary Medical Reviewer	Adam Husney, MD - Family Medicine
Specialist Medical Reviewer	Martin Gabica, MD - Family Medicine
Last Revised	December 11, 2009