The cornea focuses light and protects the internal structures of the eye. The shape of the cornea is important to the focusing of light on the retina in the back of the eye. A properly shaped cornea and healthy lens will allow this light to focus clearly, providing crisp vision. If the cornea gets hazy or cloudy, or if the shape of the cornea becomes irregular, vision can be impaired. Some causes of this include age, trauma or disease. When vision is impaired enough to affect a patient’s daily functioning, it may need to be totally or partially replaced by a corneal transplant procedure.
New technologies have made this an exciting time for corneal transplantation. Traditional corneal transplantation, known as Penetrating Keratoplasty (PK), is a highly refined procedure with positive overall outcomes. Traditional corneal transplantation techniques have evolved as well, allowing surgeons to provide even newer techniques, such as DSAEK, to patients with specific corneal needs.
A very common cause of a cloudy cornea is a damaged inside, or endothelial, layer of the cornea. The endothelial layer is one cell layer thick and can be damaged by surgery or trauma or the cells can die too quickly over time (a condition known as Fuchs' Dystrophy). When there are not enough endothelial cells, water can build in the cornea causing cloudy vision and vision loss. DSAEK is a highly refined technique that replaces just the endothelial layer of the cornea, allowing surgeons to target the specific cause of the patient’s vision loss. In the DSAEK procedure the damaged cells are stripped from the patient’s eye and replaced with a very thin back portion of a donor cornea. This procedure allows your surgeon to literally replace only the damaged area of cornea, allowing a more precise treatment and better overall results. Your surgeon uses an air bubble technique to hold the new tissue in place in the eye for the entire day of surgery so that no sutures are needed.
Surgery is often done on an outpatient basis. You may be asked to skip breakfast, depending on the time of your surgery. Once you arrive for surgery, you will be given eyedrops 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. Your eye will be held open with a lid speculum or another method.
The eyelids are gently opened. Your eye surgeon will view your eye through a microscope and measure your eye for the corneal transplant. 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 in over, your doctor will usually place a shield over your eye.
If you are an outpatient, you may go home after a short stay in the recovery area. You should plan to have someone drive you home. An examination at the doctor's office will be scheduled for the following day.
You will need to:
Your eye doctor will decide when to remove the stitches, depending upon the health of your eye and rate of healing. Usually, it will be one year before stitches are removed, but this varies depending on the specific technique used. Often, stitches are left in place permanently.
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.
Eye surgeons perform more than 40,000 corneal transplants each year in the United States. Of all transplant surgery done today, including heart, lung, and kidney, corneal transplants are the most common and successful.
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:
Any of these symptoms should be reported to your Eye Doctor immediately.
Other possible complications include:
All of these complications can be treated.
A corneal transplant can be repeated, usually with good results, but 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 year after surgery.
Even if the surgery is successful, otherexisting eye conditions, such as macular degeneration, glaucoma, or diabetic retinopathy, may limit vision after surgery. Even with such problems, a corneal transplant may still be worthwhile.
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.