Descemet’s Stripping Automated Endothelial Keratoplasty (DSAEK) is the greatest advancement in corneal surgery in decades. Dr. Friend is one of the few surgeons in northern New Jersey performing this procedure. This revolutionary breakthrough allows Dr. Friend to transplant only the sick or damaged part of a patient’s cornea, tremendously reducing healing time and the rate of complications.
The most common reasons that patients suffer from a swollen cornea is either a genetic condition, called Fuch’s dystrophy, or from damage to corneal cells that occurs during cataract surgery. The common theme with both of these conditions is a problem with the cells on the back of the cornea, known as endothelial cells. These cells keep the cornea thin by pumping out fluid. We are born with a tremendous number of these cells. However, unlike most cells, endothelial cells cannot regenerate. If an endothelial cell dies or becomes damaged, no new cell takes its place. If a critical number of endothelial cells malfunction or die, the cornea swells and the patient’s vision becomes blurry and distorted.
In Fuch’s dystrophy, endothelial cells morph into dysfunctional cells known as guttata. Many people have a very mild version of this disease that causes no symptoms. However, if more guttata form, the remaining endothelial cells cannot adequately keep fluid out of the cornea, resulting in decreased vision.
Cataract surgery always causes at least some endothelial cell damage. With most patients, this damage is insignificant because there is an abundance of healthy endothelial cells remaining that can sufficiently pump out fluid. However, patients with Fuch’s dystrophy are more at risk for swelling after cataract surgery because they may not have an adequate number of remaining healthy endothelial cells. In situations where the cataract surgery becomes complicated, even patients with previously healthy endothelial cells can have swelling due to cell damage during surgery.
Until recently, a patient with corneal swelling had few choices. There are no medications that can grow or replace endothelial cells. There is an eye drop that can reverse very mild cornea swelling, but it only works for a few hours, requiring multiple doses. For years, the only surgical option was to transplant the entire cornea, even though only the back layer of the cornea was damaged.
Recently, DSAEK radically improved the prognosis for these patients. With this procedure, Dr. Friend removes only the endothelial cells, leaving the patient with the rest of his healthy cornea intact. Dr. Friend then takes the endothelial cells from a donor cornea and transplants them into the patient.
DSAEK has many advantages for the patient. In a full-thickness corneal transplant, the surgeon needs to put in many sutures in a circle around the cornea. In DSAEK, Dr. Friend only needs to put a few sutures on the edge of the cornea. Using so few sutures greatly reduces the healing time, from over a year with a full-thickness corneal transplant to only three months with DSAEK.
In a full-thickness corneal transplant, patients tend to have much more astigmatism. This happens because even with the best surgical technique, the sutures are pulling in different directions with different tension, causing the cornea to heal with an irregular shape, known as astigmatism. Since DSAEK only has a few sutures on the cornea’s edge, the amount of astigmatism is greatly reduced. Because of astigmatism, patients with full-thickness corneal transplants are much more likely to need hard contact lenses or laser vision correction than patients who have DSAEK.
Fewer sutures mean patients also don’t have as many physical restrictions with DSAEK, since the risk of breaking a suture is much less worrisome. DSAEK is also much safer in the long run for patients because even after a full-thickness corneal transplant completely heals, the area of the cornea where the sutures were placed is always weaker than the rest of the eye. Due to this weakness, patients are more prone to damage after trauma than with DSAEK.
While DSAEK is a tremendous medical breakthrough, there are risks unique to this procedure. Patients with DSAEK are more likely to have their transplanted cornea shift off-center or improperly adhere to the rest of the cornea immediately after surgery. Therefore, there is a higher risk of needing to have a second surgery to rectify these complications. However, the success rate after a corrective procedure is very high.
For patients whose endothelial cell damage is caused by complicated cataract surgery that required an intraocular lens (IOL) placed just behind the cornea, there may need to be a surgery to replace this IOL before DSAEK. In these patients, the original IOL is removed and an IOL is then secured behind the iris. After the eye heals from the IOL exchange, there will be a safe space for the transplanted cornea in DSAEK.
