The
cornea is the
transparent front part of the
eye that covers the
iris,
pupil, and
anterior chamber. The cornea, with the anterior chamber and
lens,
refracts light, with the cornea accounting for approximately two-thirds of the eye's total
optical power. In humans, the refractive power of the cornea is approximately 43
dioptres. While the cornea contributes most of the eye's focusing power, its focus is fixed. The
curvature of the lens, on the other hand, can be adjusted to "tune" the focus depending upon the object's distance. Medical terms related to the cornea often start with the prefix "" from the
Greek word κέρας,
horn.