Our corneal specialist can often treat most of cornea problems and conditions and corneal diseases using non-surgical treatment options. However if they are not diagnosed and treated early or if they progress to where vision is compromised beyond an acceptable level, it may be necessary to perform a corneal transplant.
What Is A Corneal Transplant?
A corneal transplant is a type of eye surgery we perform in order to replace diseased, damaged or scarred corneal tissue with new healthy corneal tissue. Since damaged or scarred corneal tissue does not allow light to effectively pass into the eye and reach the retina, poor vision and even blindness may result from a damaged cornea. There are actually a number of different types of corneal transplants that we can perform.
Penetrating Keratoplasty (PKP)
This type of corneal transplant involves the surgical removal of the central two-thirds thickness of the damaged cornea. We remove the central portion of the damaged or cloudy cornea with a “cookie cutter” like instrument called a trephine, and replace it with a clear cornea obtained from the eye bank. We then very carefully sew the donor cornea into place using sutures that are thinner than a human hair. To facilitate the healing of the new transplanted cornea, we prescribe eye drops for patients who have had corneal transplants. After the new cornea has healed properly, we will remove the fine sutures or stitches he put in place during the surgery. Usually we will remove these sutures right in our office at Matossian Eye Associates. This type of transplant has the potential to provide the clearest vision after healing because there is no interface (layer) to look through. However, the healing time is longer and the use of a contact lens might be required for the clearest vision.
Descemet Stripping Endothelial Keratoplasty (DSEK)
DSEK is partial corneal thickness corneal transplant performed through a small incision, to remove and replace the inner cell layer of the cornea when it stops working properly. With this technique, we gently “strips” off the single diseased cell layer, called the Endothelium, and leaves the remaining cornea intact. Using a prepared thinly sliced donor cornea from the eye bank we are able to fold the back portion in half and inserts it through a small incision into the eye. We then use an air bubble to unfold and position the donor tissue on the recipient cornea. Within a few minutes the donor tissue attaches to the recipient without the use of any sutures. There are a number of advantages of DSEK if you are indeed a candidate:
- Your eye remains much stronger
- Visual recovery is very rapid
- DSEK causes little change in eyeglass glasses prescription
Descemet Membrane Endothelial Keratoplasty (DMEK)
DMEK is also a partial thickness corneal transplant. DMEK is indicated for patients with corneal edema after cataract surgery or Fuchs endothelial dystrophy, and otherwise healthy eyes with good visual potential. Patients with other eye diseases such as macular degeneration or glaucoma are better candidates for DSEK. The deteriorated endothelial cells are removed from the patient’s eye along with the Descemet’s membrane and an ultra thin corneal transplant from a donor consisting of a single layer of cells and Descemet’s membrane only is inserted into the eye. The patient keeps most of the outer layers of their own cornea. The transplanted layer of cells is pressed against the patient’s own cornea with a gas bubble injected into the eye and patients must lay flat on their back as much as possible until the gas bubble is absorbed after approximately 1 week. Some patients may require a second gas bubble to be injected in the eye in the office or in the operating room to help with adhesion. The final visual acuity is usually better than any other form of corneal transplantation, including DSEK. It is thought that DMEK transplants have the lowest rates of rejection compared to DSEK and PKP, but patients must still remain on steroid eye drops for a few years after surgery.
Corneal Transplants have become somewhat common in the United States as a treatment for damaged and cloudy corneas. Each year more than 40,000 people undergo corneal transplantation to restore their vision. If we find that other methods of treating your corneal disease or corneal condition are inadequate to give you good sight, we will fully discuss the risks and benefits of corneal transplantation and take the time necessary to answer all of your questions.