Descemet Stripping Endothelial Keratoplasty (DSEK) and Descemet membrane endothelial keratoplasty (DMEK) Santa Rosa, CA
The cornea is comprised of five basic layers of tissue. During a traditional corneal transplant, known as a “penetrating keratoplasty” or “PKP”, a circular disc of the full thickness of the cornea–all five layers– is removed from the center of cornea and replaced with healthy donor tissue. This new tissue is sutured in place. A full thickness corneal transplant has been a safe and effective procedure for the treatment of damaged corneas for decades. However, the recovery can be long, and often the patient will need contact lenses or glasses after the surgery to correct the astigmatism caused by the sutures. The cornea is also more fragile after this procedure and sometimes even minor trauma to the eye can dislocate the graft.
Benefits of DSEK and DMEK Versus PKP
Dr. Barth and Dr. Ni have been performing DSEK corneal transplants for patients with persistent corneal swelling and poor vision. Dr. Ni has also been routinely performing DMEK procedures, the newest generation and most technically challenging type of partial thickness transplants. These revolutionary procedures have nearly replaced the traditional corneal transplant. With a DSEK procedure, a thin sliver of healthy donor corneal tissue around 100 microns, consisting of a small portion of stroma, Descemet’s membrane, and a layer of endothelial cells is used to replace the diseased back layer of the native cornea. In DMEK, replacement tissue is closest to the cornea’s original anatomic condition, as it consists of a single layer of endothelial cells plus a 15 micron thin membrane. The advantages of the DSEK / DMEK methods of just transplanting the posterior part of the cornea are numerous:
- A much safer procedure than a full thickness corneal transplant. During a DSEK or DMEK procedure, only two small incisions need to be made to allow the microsurgical instruments to strip off the diseased endothelium from the central portion of the patients’ cornea. After the donor corneal tissue layer is prepared, it is gently folded and placed within the fluid-filled anterior chamber of the eye, beneath the patient’s cornea. Injected sterile air creates an air bubble, which causes the donor tissue to unfold and holds it in the exact location where the original tissue was removed. This is a shorter procedure, usually requiring less than half the time it takes to undergo a traditional penetrating keratoplasty. The small incision, the need for fewer or no sutures, and the shorter procedure time make the DSEK and DMEK procedures extremely safe and produce amazing visual results.
- Stronger cornea after surgery. Since only the posterior layer has been replaced, minor trauma to the eye is less likely to cause a graft dislocation.
- Much more predictable refraction. Usually one suture is used in a DSEK procedure, and no sutures in a DMEK procedure. This means smaller changes in astigmatism, nearsightedness or farsightedness after the surgery. Another benefit of using fewer sutures is that the incidence of infection or irritation from them should be greatly reduced. The eye’s refractive status is dependent on the front shape and steepness of the cornea. In the DSEK/DMEK transplant method, the front surface remains unchanged, leaving better ocular balance between the eyes.
- Quicker visual recovery. Compared to the long recovery from a standard full thickness corneal transplant, which can take up to one or two years, full visual recovery from a DSEK procedure can be as short as three months. This is due to the thinner itssue, smaller incision size, and the fact that fewer sutures are used. After DMEK procedures, patients can typically achieve driving vision within a week, with further improvement over the subsequent 1-2 months. Achieving 20/20 or 20/25 vision is also more common after DMEK than DSEK. Your surgeon will decide along with you whether you are a candidate for the latest DMEK technique.