Descemet’s Stripping Automated Endothelial Keratoplasty, or DSAEK, is a modern surgical procedure that addresses specific types of corneal damage. This technique is a partial-thickness corneal transplant, replacing only the innermost layer of the cornea. The cornea is the clear, dome-shaped front surface of the eye. DSAEK specifically targets the endothelium, a single layer of cells responsible for maintaining corneal clarity by pumping fluid out of it. When this delicate layer is compromised, fluid can accumulate, leading to swelling and cloudy vision.
Medical Conditions Treated by DSAEK
DSAEK is performed for conditions that affect the cornea’s endothelial layer, leading to fluid buildup and impaired vision. Fuchs’ Endothelial Dystrophy is a primary indication for this surgery, an inherited eye disease where endothelial cells gradually deteriorate. As these cells malfunction, the cornea swells and becomes cloudy, often causing blurry vision that is worse upon waking.
Other conditions causing endothelial failure, such as pseudophakic bullous keratopathy, can also be treated with DSAEK. This form of corneal swelling can arise as a complication of previous eye surgeries or trauma.
The DSAEK Surgical Procedure
The DSAEK procedure involves precise steps to replace the compromised inner corneal layer with healthy donor tissue. The surgeon makes a small incision, typically between 3.2 mm and 5 mm, in the eye to access the anterior chamber. Through this incision, the patient’s damaged Descemet’s membrane and endothelium are carefully removed by stripping the layer.
Next, a thin disc of donor corneal tissue, comprising the healthy endothelium, Descemet’s membrane, and a small amount of posterior stroma, is prepared. This donor tissue is then carefully folded and inserted into the eye through the small incision. Once inside, the surgeon unfolds and positions the new tissue against the back of the patient’s cornea. An air bubble is injected into the anterior chamber to gently press the donor tissue into place, allowing it to adhere to the host cornea. The small incision requires few or no stitches, promoting quicker healing.
Post-Surgery Recovery and Vision
Following DSAEK surgery, specific post-operative instructions are provided. Patients are advised to lie flat on their back, looking towards the ceiling, for 24 to 48 hours immediately after the procedure. This supine position helps the air bubble maintain continuous pressure on the newly transplanted tissue, encouraging it to adhere properly to the host cornea.
Patients will also be prescribed antibiotic and steroid eye drops to prevent infection and reduce inflammation. Blurry vision and mild irritation are common in the initial recovery period. While some patients may experience improved vision within 24 hours, full visual stabilization can take several weeks to months as the eye heals and the graft settles.
Comparison with Other Corneal Transplants
DSAEK represents a significant advancement over older corneal transplant methods. Compared to Penetrating Keratoplasty (PKP), a traditional full-thickness corneal transplant, DSAEK involves a much smaller incision. This smaller incision contributes to faster visual recovery and a reduced likelihood of induced astigmatism. The eye also maintains more of its structural integrity with DSAEK, as only a partial thickness of the cornea is replaced.
A newer procedure, Descemet’s Membrane Endothelial Keratoplasty (DMEK), further refines partial-thickness transplantation. DMEK utilizes an even thinner layer of donor tissue, consisting solely of Descemet’s membrane and endothelium. This ultra-thin graft in DMEK can lead to sharper final vision and potentially lower rates of graft rejection compared to DSAEK. However, the extreme thinness of the DMEK graft makes it more delicate and challenging to handle during surgery, which can result in a higher rate of graft dislocation, requiring a follow-up procedure to reposition the graft with an air bubble.