Endothelial keratoplasty (EK) is a cornea transplant technique that is the preferred way to restore vision when the inner cell layer of the cornea stops working properly from Fuchs’ dystrophy, bullous keratopathy, iridocorneal endothelial (ICE) syndrome, or other endothelial disorders. EK selectively replaces only the diseased layer of the cornea, leaving healthy areas intact.
There are a two types, including
Descemet's Stripping Endothelial Keratoplasty (DSEK, 2003)
Descemet's Membrane Endothelial Keratosplaty (DMEK, 2008)
Dr. Price, founder and president of the Cornea Research Foundation, was an early pioneer of this procedure and has now has surpassed 5,000 cases, performing more of these than anyone else in the world including over 2,500 DMEK cases. Currently Dr. Price and the research team are working to compile the 10-year DSEK patient outcomes and 5-year DMEK patient outcomes. We will share these findings once they become available.
How it Works
The surgeon removes the diseased inner cell layer of the cornea:
The surgeon implants healthy donor tissue through a small incision:
The surgeon then uses an air bubble to unfold and position the donor tissue against the patient’s cornea:
The small incision is either self-sealing or may be closed with a suture or two. Dr. Price routinely performs this procedure just using eye drops to numb the eye.
Compared with a traditional full thickness transplant, endothelial keratoplasty provides the following advantages:
- The eye remains much stronger and less prone to injury
- Visual recovery is much faster
- Minimal activity restrictions are required
- Minimal change is required in glasses prescription
The most common type of EK procedure is known as DSEK. In this procedure the surgeon implants the back 20-30% of the donor cornea into the patient’s eye. Patients without other eye problems usually achieve average vision of 20/30 or better within a couple of months. Drs. Francis and Marianne Price produced the first ever DSEK book, describing how the procedure is done and what it is like from the patient’s perspective. The risk of rejection from DSEK is around 12 percent, whereas full thickness transplants have around a 20 percent rejection risk.
Dr. Price helped pioneer a newer form of EK, known as DMEK. These use extremely thin donor tissue (just 5% of corneal thickness) and provide more patients with 20/20 or 20/25 than DSEK. In fact, DMEK provides 20/25 or better vision for about 3 out of 4 patients. Additionally, the risk of rejection is reduced with DMEK to less than 1 percent.
The biggest hurdle with DMEK is the preparation of the donor tissue. Basically, the endothelium and attached Descemet’s membrane has to be peeled off the back of the donor cornea. The ultra-thin DMEK grafts are so fragile that sometimes the precious donor tissue tears while separating the layers and it cannot be salvaged. Descemet’s membrane is only about 15 microns thick! So the preparation has to be done very carefully. In fact, now some eye banks are providing prepared tissue to surgeons who do not want to undertake this step in the process.
During DMEK, the patient's existing endothelium is removed and replaced with this specially prepared donor tissue. After the patient is prepped for the procedure and their diseased tissue is removed, the surgeon places the prepared donor tissue in a solution which changes it to a tinted blue color temporarily so the surgeon can better see it. The tissue is then placed into an insertion device that is similiar to a syringe. The syringe is inserted through the same small incision in the eye of the patient that was used for the removal of the diseased tissue and the new tissue is placed in the eye.
Once a DMEK graft is placed into the patient’s eye, it usually curls up into a scroll. The scroll has to be unrolled and the surgeon has to determine which side should face the recipient cornea and which side should face the inside of the eye. We have developed some techniques to help with this and the surgeon performs a test on the wake patient and asked if they can see a light before they continue to ensure the placement is correct. To unroll the scroll, the surgeon uses small puffs of air and a few surgical tools to ensure the tissue is correctly placed.
Finally, the surgeon ensures the amount of air is correct. This is an important step because the air is used to hold the tissue in the correct place. Too much air or not enough air can be problematic so it's important to have the right amount. Lastly, the surgeon sutures the small opening that was made in the patient's eye.
Typically the patient is monitored for around two hours after surgery and this is permitted to go home or to the hotel to rest and will return the next day (post-op day 1) and the following (post-op day 2) for exams and finally on a 5th day after surgery which is when they are typically released to go home.
To learn more about the details of the surgery or logistics of traveling to Indianapolis for your procedure, please visit this page.