Any condition which alters the normally smooth contour of the cornea, the curvature of the cornea, or any condition which leads to clouding of the normally crystal clear cornea, will lead to vision loss and the need for a corneal transplant.
When the cornea becomes “opaque” or gray/white from disease or injury or painful from swelling or blisters, it no longer functions as the “clear window” of the eye. It then acts more like a “soapy” window which you cannot clearly see through. Even if the rest of the eye is healthy, a cloudy cornea will obstruct clear vision. Corneal transplants are the most successful transplant in the body with success rates from 85-95%.The procedure itself is technically difficult. It is performed under an operating microscope which magnifies the eye 30 to 60 times.
The diseased cornea or “host” cornea, is cut with a round blade with a hole in its center. This is like a round cookie cutter punching a round disc of cookie dough.
The diseased tissue or disc is removed just as you would pick up the cut out cookie, leaving a rim of cookie dough on the platter. Now you have a hole in the center of the cornea just like the hole in the center of the cookie dough. The surgeon then uses the same or a slightly larger blade to cut a similar piece of tissue from a HEALTHY CORNEA from a person who has recently died. This healthy “donor” cornea is then placed into the hole where the diseased tissue was removed.
The healthy, new piece of corneal tissue is then sewn to the remaining rim of the patient’s tissue as shown in the drawing.
The eye then has a healthy, clear “new window” or corneal transplant. The stitches remain in place for 12 months and vision usually begins to return in 1 to 8 weeks after surgery. It must be remembered however, that diseases of other portions of the eye, such as disease of the lens or of the retina, can limit the final vision even if the surgery was successful and the cornea is perfectly clear. Other procedures such as cataract extraction and lens implant, intraocular lens implant removal or vitrectomy may be and often are performed at the same time as the corneal transplant.