The cornea is the clear front window of the eye. It transmits light to the interior of the eye allowing us to see clearly. Corneal injury, disease, or hereditary conditions can cause clouding, distortion, and scarring. Corneal clouding blocks the clear passage of light to the back of the eye, reducing sight sometimes even to the point of blindness. In addition, corneal injury and disease can be very painful.
What causes corneal disease and degeneration?
Infections, whether bacterial, fungal, or viral are frequent causes of severe corneal damage and ulceration. Abnormal steepening of the cornea occasionally follows cataract surgery and some aging processes can also affect the clarity and health of the cornea. Some disorders of the cornea are inherited, and can lead to corneal clouding and loss of sight.
What is a corneal transplant?
If the cornea becomes cloudy, the only way to restore sight is to replace or transplant the cornea. Corneal transplantation (keratoplasty) is the most successful of all tissue transplants. An estimated 15-20,000 corneal transplants are done each year in the United States. The success rate depends on the cause of the clouding. For example, corneal transplants for degeneration following cataract surgery and those for keratoconus both have high success rates, while corneal transplants for chemical burns have lower success rates.
What conditions may require corneal transplants?
- Corneal failure after other eye surgery, such as cataract surgery
- Keratoconus, a steep curving of the cornea
- Hereditary corneal failure such as Fuchs' corneal dystrophy
- Scarring after infections, especially after herpes
- Rejection after first corneal transplant
- Scarring after injury
What happens during corneal surgery?
Once you and your doctor decide you need a corneal transplant, your name is put on the list at the local eye bank. Before a cornea is released for transplant, the eye bank tests the human donor for the viruses that cause hepatitis and AIDS. The cornea is carefully checked for clarity. Your eye care professional may request that you have a physical examination and other special tests. If you usually take medications, ask your doctor if you should continue using them.
Surgery is often done on an outpatient basis. You will need to skip breakfast, depending on the time of you surgery. Once you arrive for surgery, you will be given eye drops and 
perhaps a sedative to help you relax. Either local or general anesthesia is used, depending on your age, medical condition and eye disease. You will not see the surgery while it is happening. You eye will be held open with a lid speculum or other method.
The eyelids are gently opened. The diseased or injured cornea is carefully removed from the eye. Any necessary additional work within the eye, such as removal of a cataract, is completed. Then the clear donor cornea is sewn into place. When the operation is over, the doctor will usually place a shield over your eye.
What to expect after surgery?
If you are an outpatient, you may go home after a short stay in the recovery area. You should plan to have someone else drive you home. An examination at the doctor's office will be scheduled for you the following day.
You will need to:
- Use the eye drops as prescribed
- Be careful not to rub or press on your eye
- Use over-the-counter pain medicine, if necessary
- Continue normal daily activities, except exercise
- Ask your doctor when you can begin driving
- Wear eyeglasses or an eye shield as advised by your doctor
If you have any questions about your home care instructions, call you doctor. Your eye doctor will decide when to remove the stitches, depending upon the health of the eye and rate of healing. Usually, it will be several months before the stitches are removed.
What are the risks of corneal transplant surgery?
Corneal transplants are rejected 5% to 30% of the time. The rejected cornea clouds and vision deteriorates. Most rejections, if treated promptly, can be stopped with minimal injury.
Warning signs of rejection are:
- Persistent discomfort
- Light sensitivity
- Redness
- Change in vision
Any of these symptoms should be reported to your surgeon immediately.
Other possible complications include:
- Infection
- Bleeding
- Swelling or detachment of the retina
- Glaucoma
Can these complications be treated?
All of these complications can be treated. A corneal transplant can be repeated, usually with good results, but the overall rejection rates for repeated transplants are higher than for the first transplant. Irregular curvature of the transplanted cornea (astigmatism) may slow the return of vision but can also be treated. Vision may continue to improve up to a year after surgery. Even if the surgery is successful, other existing eye conditions, such as macular degeneration (aging of the retina), glaucoma or diabetic retinopathy, may limit vision after surgery. Even with such problems, a corneal transplant may still be worthwhile.
Requirements of successful corneal surgery
A successful corneal transplant requires care and attention on the part of both patient and physician. However, no other surgery has so much to offer when the unhealthy cornea is deeply scarred or swollen. Corneal transplant surgery would not be possible without the thousands of generous donors and their families who have donated corneal tissue so that others may see.
What happens after surgery?
Return of best vision after corneal transplant surgery may take up to a year after the operation, depending on the rate of healing and the health of the rest of the eye. As in any kind of transplant, rejection of the donated tissue can take place. The major sign of rejection are redness of the eye or worsening of vision. If these occur, promptly return to your eye care professional, even if it is years after the original operation.
If you are interested in donating your corneas to the Lion’s Medical Eye Bank, click here