The cornea is the eye’s outermost layer. It is a clear dome of tissue that allows light to enter the eye. If the cornea becomes diseased or damaged, it can distort or even block the normal path of light into the eye. When this happens, light does not focus normally on the retina, the layer at the back of the eye that is responsible for sight. As a result, there can be significant loss of vision in the affected eye.

When corneal conditions cause serious vision problems that can’t be reversed, a corneal transplant often is the best solution. In a corneal transplant, an eye surgeon first removes the diseased or damaged area of the cornea. The removed tissue then is replaced by a section of healthy cornea that has been taken from the eye of a deceased donor.