The cornea is the transparent front part of the eye which provides most of an eye's optical power. Together with the lens, the cornea refracts light and, as a result, helps the eye to focus.

The cornea might lose its transparency due to keratoconus (a degenerative disorder of the eye in which structural changes within the cornea cause it to thin and change to a more conical shape than its normal gradual curve), dystrophia (changes in the texture, color of cornea), infection, burns, or injuries. In corneal transplatation, a damaged or diseased cornea is replaced by donated corneal tissue.

Depending on the layer kept in cornea, lamellar (partial) or penetrating (whole) keratoplasty may be applied.

Among all transplantation surgeries, corneal transplantation is the easiest and most successful one. However, the healing and follow-up procedures, patient-doctor relationship are also as important as the surgery itself. Success rate is 70% to 95%.