DMEK surgery, known as Descemet’s Membrane Endothelial Keratoplasty, is a specialized corneal transplant procedure. It is designed to restore vision by precisely replacing a specific, very thin layer of the cornea. This procedure represents an advanced approach in treating certain vision-impairing conditions, focusing on accuracy and minimal intervention.
Understanding DMEK Surgery
DMEK, or Descemet’s Membrane Endothelial Keratoplasty, is a partial-thickness corneal transplant. This procedure targets the innermost layers of the cornea: the Descemet’s membrane and the corneal endothelium. The corneal endothelium is a single layer of cells that lines the back surface of the cornea. These cells act like tiny pumps, removing excess fluid to maintain the cornea’s transparency for sharp vision.
When the endothelial cells are damaged or dysfunctional, they can no longer effectively pump fluid, leading to corneal swelling and blurred vision. DMEK addresses this by replacing only this diseased, ultra-thin layer with a healthy donor layer. The donor tissue used in DMEK is remarkably thin, typically ranging from 10 to 20 microns thick, which is thinner than a human hair or comparable to four times thinner than a sheet of paper. This precise replacement aims to restore the cornea’s natural clarity.
Conditions Requiring DMEK
DMEK surgery treats conditions where corneal endothelium damage leads to swelling and blurred vision. One common inherited condition treated with DMEK is Fuchs’ endothelial dystrophy, a progressive disorder where the endothelial cells gradually deteriorate over time. Patients with Fuchs’ dystrophy often experience vision that is blurrier in the morning and may improve throughout the day, as fluid accumulates in the cornea overnight.
Another condition that often necessitates DMEK is pseudophakic bullous keratopathy. This condition can occur after cataract surgery if the endothelial cells are damaged during the procedure, leading to persistent corneal swelling. In both conditions, impaired fluid-pumping causes the cornea to become cloudy, making DMEK an effective treatment to restore clarity.
The DMEK Surgical Procedure
Patients typically receive local anesthesia, numbing the eye while awake. The surgeon makes a tiny 3-millimeter incision on the side of the cornea. Through this small opening, the diseased Descemet’s membrane and its attached endothelial cells are carefully removed from the back surface of the patient’s cornea. This step requires delicate handling to preserve the surrounding healthy corneal structures.
The donor tissue, consisting only of the healthy Descemet’s membrane and endothelium, is prepared. This ultra-thin tissue is typically rolled or scrolled for insertion into the eye through the small incision. Once inside the eye, the surgeon carefully unrolls and positions the new donor graft against the inner surface of the patient’s cornea. An air or gas bubble is then injected into the eye’s anterior chamber to press the new tissue against the cornea, helping it adhere securely without sutures. The entire procedure can be completed in as little as 10-15 minutes, though it may take up to an hour.
Recovery and Post-Operative Care
Post-DMEK surgery, patients play an active role in recovery, particularly regarding positioning. Patients are advised to lie flat on their back, looking up, for 3 to 7 days. This supine positioning helps the air or gas bubble press the donor tissue against the inner cornea, promoting attachment and healing. Short breaks for walking or using the restroom are usually permitted.
Eye drops, including antibiotics and steroids, are prescribed to prevent infection and control inflammation. These drops must be used exactly as directed for several weeks or months. Visual recovery can begin within weeks, with significant improvement often seen within 1 to 3 months, though full visual stability may take longer. Patients should avoid rubbing their eyes, strenuous activity, heavy lifting, and swimming to protect the healing eye. Frequent follow-up appointments monitor graft adherence and overall eye health.
Advantages and Potential Complications
DMEK offers several advantages over older corneal transplant techniques. Because it replaces only the diseased, innermost layer of the cornea, it results in faster visual recovery compared to full-thickness transplants. Patients often experience noticeable improvement in vision sooner, sometimes within weeks. Another significant benefit is a lower risk of graft rejection, as less foreign tissue is transplanted. DMEK also leads to better visual outcomes and minimal disruption to the eye’s natural anatomy.
While DMEK is a successful procedure, potential complications can occur, though they are rare. The most common complication is graft detachment, where the transplanted tissue separates from the cornea. This may require “re-bubbling,” where another air or gas bubble is injected to reattach the graft. Other complications include infection, elevated eye pressure (glaucoma), or graft failure. Surgeons assess patient suitability to minimize these risks.