Descemet’s Stripping Automated Endothelial Keratoplasty (DSAEK) and Descemet’s Membrane Endothelial Keratoplasty (DMEK)
DSAEK and DMEK are techniques that can help some patients who previously required a full thickness corneal transplant. Both the conventional corneal transplant technique and DSAEK/DMEK require use of a donor cornea, but DSAEK/DMEK replace only the diseased posterior section of the cornea. This procedure, which requires minimal suturing, allows more rapid visual restoration, less discomfort, and a reduced risk of some sight-threatening complications.
The cornea is the clear window at the front of the eye that bends and helps focus light onto the back of the eye (the retina). In order for vision to be clear, the cornea must be clean and clear. Corneal disease can cause the cornea to become opaque or cloudy, preventing light from passing through clearly.
With a conventional corneal transplant, the full thickness of the cornea is completely removed, and a whole new donor cornea is sutured around the circumference of the cornea. These sutures can remain in the eye for over a year and can cause the cornea to take on an irregular shape during the healing process that is difficult to correct with glasses or contact lenses. This can result in less than optimum postoperative vision. DSAEK and DMEK, on the other hand, involves removing only Descemet’s membrane and the damaged endothelial cells and leaves the surface of the cornea intact. The surgery is usually performed on an outpatient basis.
While DSEAK and DMEK are both partial thickness corneal transplants, the difference between the procedures is based on the thickness of the transplanted tissue. Your doctor will determine which of these transplants is most appropriate for your specific condition.
What to expect on surgery day
You will arrive at the surgery center about an hour prior to your procedure. Once you have been checked in you may be offered a sedative to help you relax. You will then be prepared for surgery. The area around your eyes will be cleaned and a sterile drape may be applied around your eye. An injection of anesthetic may be given around your eye to help with pain.
Next, a small incision will be made to allow the surgeon to strip away the diseased Descemet’s membrane and damaged endothelial cells. The bottom 10-20% of a donor cornea that has healthy endothelial cells attached to its Descemet’s membrane will be inserted through the same incision. After it is placed in position, an air bubble will be used to hold the transplanted tissue in place.
After your DSAEK/DMEK procedure
Immediately after the procedure, you will be taken into recovery where you will lie down for about an hour to let the air/gas bubble continue to press against the tissue to secure it in place. Your eye will be patched before you leave. Antibiotic eye drops will be used for a week or so to help prevent infection, and a mild steroid eye drop will need to be used for a year or so to help prevent rejection.
You will be asked to lie flat (at home) for 48-72 hours following the surgery. You should be able to resume normal activities after that. With conventional corneal transplantation, your vision typically does not improve for many months, while with DSAEK/DMEK, you may experience visual improvement within weeks. If you need transplants in both eyes, DSAEK/DMEK allows you to have the second transplant within months, versus a year or more if you were to have a conventional transplant.
In order to make your DSAEK/DMEK procedure a success, it is important that ALL scheduled appointments be kept and ALL medications are used as directed. Any pain, redness, or reduced vision should be reported immediately.
The decision to have DSAEK/DMEK is an important one that only you can make. The goal of any vision restoration procedure is to improve your vision. However, we cannot guarantee you will have the results you desire. Rejection could happen (although rarely) at any time in the future. However, if the transplanted tissue should be rejected, it is usually possible to have the procedure successfully repeated.