The cornea of the eye is the outer lens, the protective layer that covers the iris and the pupil. Certain conditions can cause damage the cornea. It might bulge outward, show clouding or swelling, undergo thinning, or get scarred. Sometimes, ulcers can develop in the cornea, or eye surgery can damage it. Certain medications can cause the cornea to become inflamed. When this happens, one possibility is a cornea transplant, in which a donor cornea is implanted in the patient’s eye.
Compared to other body parts, corneas have a relatively short waiting time, because most would-be donor corneas are suitable for transplantation, unlike other organs, which are likely to be damaged. However, it’s important that the donor and the recipient be closely matched in size; ill-fitting cornea transplants generally don’t take. Before the procedure is performed, the recipient undergoes a thorough eye exam, including measurements of the eye, and may get treatment for other, unrelated eye health issues that may affect the success of the operation. The procedure itself is performed with anesthetic, but obviously the patient’s eye must remain open during the surgery.
Recovery ordinarily takes a long time, though the patient only needs an eye shield for a day or two, and then at night for about a week. Eyedrops are used to help prevent infection and ease the pain of the new cornea settling in. The patient will generally require weekly eye exams for up to the first year after surgery to monitor the progress of the transplant and make sure the eye is healing properly, and monthly exams after that.
However, a new procedure called Descemet membrane endothelial keratoplasty may mean faster recovery times and better vision after surgery. The Descemet membrane is the layer of cornea closest to the back, and which helps the back layer heal from injury. For eligible patients, DMEK uses a much smaller incision than the usual technique, meaning a faster recovery time and greater visual acuity after surgery, often 20/25 as compared to 20/40 or worse for the older procedure.