Corneal Transplant
The cornea is normally a clear layer of tissue covering the front of the eye, similar to a watch crystal. Its purpose is to refract or bend light rays as they enter the eye, allowing them to focus on the retina. In cases where the cornea has become clouded as a result of disease, swelling, scarring, infection, or chemical burns, a corneal transplant (also known as a corneal graft, or as a penetrating Keratoplasty) is sometimes necessary to restore functional vision. This procedure involves the removal of the central portion called a button of the diseased cornea and replacing it with clear healthy donor button. The donor cornea button is sewed into the defect created by removal of the diseased cornea. If a cataract is present, it is removed at this time. Tiny hair-thin sutures or stitches are used to anchor the graft to the host tissue.
The success rate of
corneal transplant is about 85%. However, factors such as glaucoma, retinal
degeneration, or optic nerve disease may affect the final visual result even if
the surgery is successful.
The procedure usually takes approximately one hour and is performed with local
anesthesia on an outpatient basis. After the surgery, a plastic shield or
glasses should be worn at all times to avoid accidentally rubbing, bumping or
hitting the eye. Drops are prescribed to prevent rejection of the donor cornea.
During the postoperative period, the surgeon monitors the cornea’s healing with
special computer mapping called corneal topography. This allows the doctor to
evaluate the shape of the new cornea and remove sutures as needed to control
astigmatism.
In most cases, vision returns very gradually. The healing process may vary greatly from one individual to the next. Some may enjoy improved vision within a few months after surgery, for others, it may take up to a year.