A cornea transplant, also referred to as keratoplasty or a corneal graft, replaces damaged tissue on the clear front surface of the eye. When disease or injury damages the cornea, vision is affected. Light that enters the eye becomes scattered, resulting in blurred or distorted vision. When the cornea is severely scarred or damaged, a corneal transplant is needed to restore functional vision.
Keratoplasty is a commonly performed procedure and is considered one of the most successful types of tissue transplants. According to the National Keratoconus Foundation, over 40,000 cornea transplants are done annually in the United States.
In recent years, an innovative type of corneal transplant called Descemet’s Stripping Endothelial Keratoplasty (DSEK) has gained popularity. This new procedure removes a smaller and thinner portion of the cornea. In 2009, the American Academy of Ophthalmology declared DSEK to be superior to traditional surgery as it may provide better vision outcomes and more eye stability, as well as fewer risks. However, when the majority of the cornea is damaged, a more extensive removal may still be necessary for a successful transplant.
Criteria for a Corneal Transplant
A multitude of reasons indicate candidacy for a corneal transplant. Possible reasons include:
- Eye diseases, such as keratoconus
- Complications from laser surgery, such as LASIK
- Extreme inflammation on the cornea
- Scarring as a result of infections, such as eye herpes or fungal keratitis
- Thinning of the cornea and an irregular shaped cornea
- Hereditary factors
- Corneal failure due to previous surgical procedures
- Chemical burns or injuries that damaged to the cornea
Cornea Transplant Procedure
After a patient has been recommended and approved for a corneal transplant to restore vision, their name is added to a list at an eye bank. The United States has a highly advanced eye bank system, and the typical wait time for a donor eye is one to two weeks. The tissue of donor corneas is carefully checked for clarity and screened for disease before it is released for transplant.
The surgery is usually performed as an outpatient procedure and does not require hospitalization. General or local anesthesia may be used, depending on the patient’s preference, age, and overall health condition. Local anesthesia is injected into the skin around the eye, which relaxes the muscles that control movement and blinking, while eye drops numb the eye itself.
Once the anesthesia takes effect, the surgeon inspects and measures the damaged corneal area to determine the size of the transplant. The eyelids are held open during this time. The surgeon then removes a round, button-shaped piece of corneal tissue and replaces it with a nearly identical-sized button of donor tissue. The new, healthy tissue is then sutured into place. The entire procedure takes about one to two hours.
After the surgery, a plastic shield must be worn over the eye to protect it from accidental bumps or rubbing.
Rejection of the Corneal Graft
Although the vast majority of cornea transplants are successful, sometimes the new tissue is rejected. Warning signs of rejection include:
- Extreme sensitivity to light
- Redness
- Pain
- Decreased vision
These symptoms can occur as early as one month after the surgery or as late as five years later. Medications can be prescribed to reverse the rejection process. If the corneal graft fails completely, the transplant can be repeated and the outcome is generally positive. However, the risk of rejection increases with the number of corneal transplants.
Recovery and Healing
A corneal transplant may take up to a year or longer to fully heal. Initially, vision is blurry and the transplant area may be swollen and thicker than the rest of the cornea. As vision improves, patients can resume normal daily activities and most people can return to work within 3-7 days after surgery, but heavy lifting and exercise should be avoided for a few weeks. Steroid eye drops must be used for several months to help the body accept the transplant, and eyeglasses or a protective shield must be worn for safety. Stitches may be removed at any time between 3 months and over a year, depending on healing progress. Astigmatism may occur due to an irregular corneal surface, adjustments to the sutures may be made to reduce this issue.
Vision after a Cornea Transplant
The process of regaining vision after a cornea transplant can take up to a year. Eyeglasses or contact lenses are typically required immediately after surgery as the curvature of the transplant may not match the natural curve of the cornea. Once healing is complete and stitches are removed, laser surgery such as LASIK or PRK may be performed to reduce the need for glasses or contacts. If there is an irregular corneal surface, rigid gas permeable (GP) contact lenses may be used for vision correction.