DSAEK
Peoria and Bloomington, Illinois
The "No-Stitch" Corneal Transplant
DSAEK is a corneal transplant technique in which the unhealthy inside layer of the cornea is surgically removed and replaced with healthy donor tissue obtained from the Eye Bank. Traditionally, when patients need a corneal transplant, the entire thickness of the cornea is removed and a new cornea is then sutured into place. This cornea transplant procedure is called a penetrating keratoplasty. This is now no longer necessary in certain diseases of the cornea where only the inside lining of the cornea is affected by the disease.
The inside lining cells of the cornea are called the endothelial cells. These cells act as a pumping mechanism to allow nutrition from inside of the eye to reach the corneal tissue, but they also pump fluid out of the corneal tissue so that it remains clear. In diseases such as Fuchs' endothelial dystrophy, these cells no longer function correctly and there are not enough of these cells to keep up with the flow of fluid. Therefore, the cornea becomes swollen and cloudy and the vision becomes unclear.
Figure 1 - Unhealthy monolayer of endothelial cells attached to Descemet's membrane. The middle diagram illustrates a cross section of an over hydrated swollen cornea. The top layer of epithelial cells have formed bullae or blisters (a) and the stroma is thickened with vacuolated spaces (b) both of which are the result of over hydration. A sparse covering of stressed endothelial cells lies over a thickened Descemet's membrane (c). The rightmost figure depicts large, low density, irregularly shaped endothelial cells.
Traditionally, the entire corneal thickness was removed and a new cornea was transplanted into its place with healthy endothelial cells. This has been a very successful procedure but takes approximately nine-to-twelve months in healing to allow best corrected visual acuity. In addition, in the early stages, the vision can be quite blurry and no manipulation can take place within the first four months after surgery.
The first four months after surgery are simply used to monitor for any rejection and infection and allow for healing. The healing takes longer in the cornea because there are no blood vessels in the cornea. After four months, selective suture removal is then done on an every two week basis to adjust for astigmatism, and once the astigmatism is adjusted, the vision can usually be corrected with glasses.
With the DSAEK procedure, there are no corneal sutures involved. Therefore, the patient's pre-existing astigmatism or non-astigmatism will remain the same. The healing process of a full-thickness corneal incision will no longer have to take place. The visual recovery will be much more rapid, and the patient is then able to return to normal activity, usually within two months, instead of nine-to-twelve months.
The DSAEK Procedure
DSAEK is done on an outpatient basis. The patient will be able to return home that same day with no hospitalization required. The usual course takes slightly over two hours at the surgery center for the entire procedure and postoperative instructions.
The patient is taken to the operating room and sedated. The eye is then anesthetized and the procedure is begun.
DSAEK begins with a small incision just outside of the corneal region which allows entry into the anterior chamber. The incision that is made to enter the anterior chamber is similar to a cataract incision in that it seals without sutures. The patient's nonfunctioning endothelial cells are then surgically removed. The donor tissue is retrieved from the donor cornea. This donor tissue carrying the new endothelial cells is then placed within the anterior chamber and against the inside of the patient's cornea. An air bubble is placed within the patient's anterior chamber to hold the DSAEK transplant in position.
Figure 2 - The new DSAEK transplant with healthy endothelial cells is placed into the anterior chamber.
Figure 3 - Depicts anterior chamber full of air with a well-positioned DSAEK transplant.
The air bubble is left in place as the patient is taken to the postoperative area. The patient is asked to remain in the face-up position for approximately forty-five minutes to allow the endothelial cells to begin attaching to the inside of the cornea. After this time, the patient is then sat upright at a microscope, and a portion of the air bubble is removed.
The patient is discharged from the surgery center using standard eye drops. On the first postoperative visit, the eye pressure is checked and the attachment of the DSAEK transplant is then assured. As the new endothelial cells from the DSAEK transplant begin functioning, the patient's own cornea should begin to clear within the next one-to-two weeks.
With the DSAEK procedure, the postoperative course is considerably shorter than for penetrating keratoplasty and the number of postoperative visits considerably less, allowing for a much more rapid visual rehabilitation. In addition, the structural integrity of the eye is maintained.
I find the DSAEK procedure to be an exciting advancement in corneal transplant surgery and am happy to be able to offer it to our Gailey Eye Clinic patients and referred patients with corneal dystrophy.
Please contact our office today to learn more about the DSAEK procedure.