The cornea is unique
It's unique in that it is the only completely clear tissue in the body. It is the first and most powerful refractive surface light encounters when it enters your eye. The health of the cornea is critical to good vision, and diseases of the cornea can prevent clear vision, even when the rest of your eye is perfectly healthy.
Diseases such as Keratoconus, Fuch’s Dystrophy and Dry Eye can dramatically alter light entering your eye resulting in poor vision. When the cornea becomes opacified, swollen or irregularly shaped, surgical removal of the diseased tissue and transplantation of healthy tissue in its place may be necessary. The cornea is layered (much like an onion skin), consisting of three major layers. Many corneal diseases affect only one of those layers. As such, with advances in corneal surgery, I am able to remove and replace only those layers affected by disease, which lowers the affect these transplants have on vision and the risks of rejection.