A corneal transplant involves replacing a diseased or scarred cornea with a new one. When the cornea becomes cloudy, light cannot penetrate the eye to reach the light-sensitive retina. Poor vision or blindness may result.
In corneal transplant surgery, the surgeon removes the central portion of the cloudy cornea and replaces it with a clear cornea, usually donated through an eye bank. A trephine, an instrument like a cookie cutter, is used to remove the cloudy cornea. The surgeon places the new cornea in the opening and sews it with a very fine thread. The thread stays in for months or even years until the eye heals properly (removing the thread is quite simple and can easily be done in an ophthalmologist's office).
Following surgery, eye drops to help promote healing will be needed for several months.
Corneal transplants are very common in the United States; about 40,000 are performed each year. The chances of success of this operation have risen dramatically because of technological advances, such as less irritating sutures, or threads, which are often finer than a human hair; and the surgical microscope.
Corneal transplantation has restored sight to many, who a generation ago would have been blinded permanently by corneal injury, infection, or inherited corneal disease or degeneration.
COMPLICATIONS WITH CORNEAL TRANSPLANTS
Even with a fairly high success rate, some problems can develop, such as rejection of the new cornea. Warning signs for rejection are decreased vision, or increased redness, pain, and sensitivity to light. If any of these last for more than six hours, you should immediately call your ophthalmologist.
Rejection can be successfully treated if medication is administered at the first sign of symptoms.
A study supported by the National Eye Institute (NEI) suggests that matching the blood type of the recipient with that of the cornea donor may improve the success rate of corneal transplants in people at high risk for graft failure.
Approximately 20% of corneal transplant patients--between 6000-8000 a year--reject their donor corneas. The NEI-supported study, called the Collaborative Corneal Transplantation Study, found that high-risk patients may reduce the likelihood of corneal rejection if their blood types match those of the cornea donors.
The study also concluded that intensive steroid treatment after transplant surgery improves the chances for a successful transplant.
ALTERNATIVES TO CORNEAL TRANSPLANTS
From The National Eye Institute (NEI), the Federal government's leading agency for vision research)