The cornea is the transparent, dome-shaped front surface of the eye that focuses light onto the retina. Descemet’s Stripping Automated Endothelial Keratoplasty (DSAEK) is a modern, minimally invasive corneal transplant that addresses clouding caused by damage to the innermost layer of the cornea. This procedure selectively replaces only the diseased inner tissue with a healthy donor graft, leaving the majority of the patient’s own cornea intact. DSAEK offers a targeted approach to restoring corneal clarity and improving vision.
Understanding Endothelial Dysfunction and DSAEK
The innermost layer of the cornea, known as the endothelium, is a single sheet of cells that constantly pumps fluid out of the cornea. This pumping action maintains the precise state of dehydration necessary to keep the cornea crystal clear. When endothelial cells are lost or fail to function correctly, this fluid pump mechanism breaks down, causing water to accumulate. This fluid buildup leads to corneal swelling (edema), which causes the cornea to become cloudy and scatter light, resulting in blurred vision. Patients often describe this sensation as looking through a foggy shower door, especially upon waking. The most common underlying causes requiring DSAEK are Fuchs’ Endothelial Dystrophy, a genetic disorder causing premature endothelial cell loss, or pseudophakic bullous keratopathy (corneal swelling after cataract surgery). DSAEK replaces the dysfunctional inner layer—the Descemet’s membrane and the endothelium—with healthy, functioning donor tissue.
DSAEK vs. Traditional Corneal Transplant
DSAEK is a partial-thickness transplant, a significant advance over the older full-thickness procedure, Penetrating Keratoplasty (PKP). PKP involves removing and replacing the entire central portion of the cornea, necessitating a large incision and numerous sutures. DSAEK replaces only the posterior layer (Descemet’s membrane, endothelium, and a thin layer of stroma), inserted through a small surgical incision, typically 3 to 5 millimeters. The advantages of DSAEK stem from this minimally invasive approach. Because the majority of the patient’s cornea remains, the eye maintains structural integrity, reducing the risk of injury or rupture. Avoiding the full-thickness incision eliminates the need for sutures, which reduces the risk of complications like infection or irregular astigmatism. DSAEK patients generally experience faster initial visual recovery and a lower risk of graft rejection compared to PKP.
The Surgical Process and Recovery Timeline
The DSAEK procedure is typically performed under local anesthesia with sedation and takes about an hour. The surgeon makes a small, self-sealing incision on the side of the eye, similar to the approach used in cataract surgery. Through this opening, the surgeon removes the patient’s damaged Descemet’s membrane and dysfunctional endothelium from the back surface of the cornea. The healthy donor tissue, prepared to include the endothelium and a thin layer of stroma, is gently folded and inserted into the eye. Once inside, the graft is unfolded and precisely positioned against the back of the patient’s remaining cornea. A sterile air or gas bubble is then injected into the eye’s anterior chamber to push the donor tissue against the recipient cornea, securing it in place by physical pressure.
The immediate recovery requires supine positioning (lying flat on the back) as much as possible for the first 24 to 72 hours following surgery. This ensures the buoyant air or gas bubble floats upward, maintaining continuous pressure on the graft to encourage it to adhere permanently to the cornea. Initial vision will be significantly blurred due to the air bubble, which gradually dissipates over the first few days. Patients are typically able to return to non-strenuous daily activities within one to two weeks, although heavy lifting and strenuous exercise must be avoided for approximately one month.
Expected Visual Results and Potential Complications
Visual improvement is often noticeable within the first few weeks, but maximal visual acuity typically takes three to six months as the cornea fully clears and stabilizes. While the procedure significantly improves vision, most patients still require glasses or contact lenses to achieve their best-corrected vision due to natural refractive changes. DSAEK predictably causes a moderate hyperopic (farsighted) shift, which is considered if the procedure is combined with cataract surgery.
The most common complication is graft detachment, where the donor tissue shifts or separates before full adherence. This occurs in a small percentage of cases and often requires a repeat procedure called a “re-bubble,” where the surgeon injects a new air or gas bubble to reposition the graft. Graft rejection, while less common than with full-thickness transplants, is another risk requiring immediate medical attention.
The symptoms of graft rejection are remembered by the acronym RSVP:
- Redness
- Sensitivity to light
- Vision loss or blurriness
- Pain
Graft rejection rates are low, but patients at higher risk, such as those with pre-existing glaucoma or those of African-American descent, may require long-term use of steroid eye drops to suppress the immune response. Graft failure can also occur over time due to continuous endothelial cell loss, potentially necessitating a second transplant.