A cornea transplant replaces diseased or scarred corneal tissue with healthy tissue from an organ donor. Cornea transplants are performed routinely and have a reasonable success rate. In fact, cornea grafts are the most successful of all tissue transplants.
There are two main types of cornea transplants:
A transplant or graft replaces central corneal tissue that is damaged due to disease or eye injury with healthy corneal tissue donated from a local eye bank. An unhealthy cornea affects your vision by scattering or distorting light and causing glare and blurred vision. When these problems are severe, a corneal transplant may be necessary to restore your functional vision.
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.
A healthy, clear cornea is essential for good vision. If your cornea is damaged due to eye disease or eye injury, it can become swollen, scarred or severely misshapen and distort your vision. A cornea transplant maybe necessary if eyeglasses or contact lenses can't restore your functional vision, or if painful swelling can't be relieved by medications or special contact lenses.
Certain conditions that may require treatment by transplant or graft include:
Once you and your eye doctor decide a corneal transplant is the best option, your name is placed on a list at a local eye bank. Unlike other types of transplants, corneas do not need to be "matched" and the surgery typically can be scheduled within a few weeks.
Before a donor cornea is released for use in transplant surgery, it is checked for clarity and screened for the presence of diseases such as hepatitis and AIDS in accordance with the Eye Bank Association of America's strict medical standards and FDA regulations. Only corneas that meet these stringent guidelines are used in corneal transplant surgery to ensure the health and safety of the graft recipient.
Your ophthalmologist may request that you get medical clearance from your primary care physician prior to the surgery. You may also be asked to discontinue aspirin or certain blood thinners.
Your eye surgeon will first administer either local or general anesthesia, depending on your health, age, eye disease, and whether or not you prefer to be asleep during the procedure.
If local anesthesia is used, intravenous sedation is given and then an injection is made into the skin around your eye.to relax the muscles that control blinking and eye movements. There will also be injections around the eyeball to numb your eye.
After the anesthesia has taken effect, an instrument called a lid speculum is used to keep your eyelids open.
Traditional corneal transplant surgery (penetrating keratoplasty or PK): A circular button-shaped, full-thickness section of tissue is removed from the diseased or injured cornea. A matching full-thickness "button" from the donor tissue is then positioned and sutured into place. PK surgery generally takes one to two hours and most procedures are performed on an outpatient basis.
Inner layer cornea transplant (endothelial keratoplasty or EK): In the past decade, EK has been introduced for certain corneal conditions. It selectively replaces only the innermost layer of the cornea (endothelium) and leaves the overlying healthy corneal tissue intact. The endothelium controls the fluid balance in the cornea, and if it becomes damaged or diseased, this can caused significant corneal swelling and loss of vision.
In EK, the surgeon makes a small incision in the eye and places a thin disc of donor tissue containing a healthy endothelial cell layer on the back surface of your cornea. An air bubble is used to position the new endothelial layer into place. Endothelial keratoplasty surgery generally takes about one hour. After the surgery, you may be asked to lie on your back in the recovery room for 30-45 minutes to allow the new cornea tissue to attach prior to removing some of the air bubble. You then will need to lie on your back for the next 24 hours, with short breaks for eating or using the bathroom, while an air bubble remains in your eye to enhance attachment of the graft.
The most common type of EK procedure is called Descemet's Stripping Endothelial Keratoplasty, or DSEK. Endothelial keratoplasty has several advantages over full-thickness penetrating keratoplasty, including:
The EK corneal graft procedure has become the preferred technique for patients with Fuch's dystrophy and other endothelial disorders of the cornea. However, traditional full-thickness PK is still the most appropriate option when the majority of your cornea is diseased or scarred.
If your surgery was an outpatient procedure, you will go home after a short stay in the recovery area. You should plan on having someone else drive you home. There will be a patch and shield over your eye. An examination at the doctor's office will be scheduled for the following day. You may experience mild to moderate pain, tearing and irritation for a few days to a couple weeks after surgery. Pain medication will be prescribed only as needed.
Total corneal transplant recovery time can be up to a year or longer. Initially, your vision will be blurry for the first few months—and in some cases may be worse than it was before—while the new cornea is healing.
As your vision improves, you gradually will be able to return to your normal daily activities. For the first several weeks, heavy exercise and lifting are prohibited. However, you may be able to return to work within a week or two after surgery, depending on your job requirements and how quickly your vision improves.
Steroid eye drops will be prescribed for at least 6 months, and often longer, to reduce inflammation and prevent rejection. Antibiotic and other drops are also given to help prevent infection and to reduce discomfort and swelling. You should keep your eye protected at all times by wearing a shield or a pair of eyeglasses so that nothing inadvertently bumps or enters your eye.
If stitches were used in your surgery, they usually are removed three to ten months post-surgery, depending on the health of your eye and the rate of healing. Adjustments can be made to the sutures surrounding the new corneal tissue to help reduce the amount of a stigmatism resulting from an irregular eye surface.
As with any type of surgery, always follow the instructions of your eye surgeon to help minimize corneal transplant complications and expedite healing.
Like any other surgical procedure, a corneal transplant comes with certain risks, but for most people, having their vision improved or restored outweighs the potential complications associated with corneal transplant surgery.
Complications of a corneal transplant can be significant, but are fortunately uncommon, and can include corneal graft rejection, eye infection, elevated eye pressure, macular swelling, and retinal detachment.
Rejection of the donor tissue is the most serious complication after a corneal transplant and occurs in 5 to 10 percent of patients. Transplant rejection occurs when your body's immune system detects the donor cornea as a foreign body and attacks and tries to destroy it. Rejection signs may occur as early as one month or as late as several years after surgery.
Recognizing the main warning signs of corneal transplant rejection is the first step to preventing graft failure. These can be remembered using the acronym RSVP.
Once identified, your eye doctor will prescribe medication that can help reverse the rejection process. If rejection is detected early, the graft will be successfully preserved 9 out of 10 times.
If the rejection is not reversed and the graft fails, corneal transplant surgery can be repeated. While repeat surgery generally has good outcomes, overall rejection rates increase with the number of corneal transplants you have.
Your eyesight should gradually improve a few weeks after a corneal graft, but it could take anywhere from a couple of months up to a year to have stable vision. The healing time is longer after a full thickness graft compared to an endothelial graft.
Even if the surgery is successful, other existing eye conditions, such as muscular degeneration, glaucoma, or diabetic retinopathy, may limit vision after a corneal transplant. Even with such problems, a corneal transplant may still be worthwhile.
A successful corneal transplant requires care and attention on the part of both the patient and physician. However, no other surgery has so much to offer when an unhealthy cornea is limiting a patient's vision.
Post-surgery refraction is somewhat unpredictable after a PK because the curve of the new corneal tissue can't match exactly the curve of your natural cornea, and large amounts of astigmatism will often present a challenge when fitting those patients with glasses afterward. After EK, there is often less astigmatism.
Mild refractive errors caused by corneal transplant surgery can be corrected with glasses; otherwise contact lenses are required.
Rigid gas permeable contact lenses, also known as RGP, usually are the most suitable contacts for corneal transplant patients due to the irregularity of the cornea after a transplant. However, soft contact lenses or a rigid/soft hybrid lens often are an option as well.
Because your vision will fluctuate during the first few months following your surgery, it is advisable to wait until your eye doctor tells you your vision is stable before you fill an eyeglass prescription or are fitted for contact lenses.
Andersen Eye Associates proudly serves the Greater Saginaw region including Flint, Frankenmuth, Bay City, Midland, Bridgeport, Bad Axe, Mount Pleasant, and surrounding areas.