Corneal Transplant: Expert Eye Surgery for Vision Restoration

Types of Corneal Transplant Procedures

There are several techniques available, each tailored to treat specific conditions affecting the cornea. The choice of procedure depends on the area and extent of the damage, as well as the overall health of the eye.

Traditional Full-Thickness Transplants: Penetrating Keratoplasty (PK)

Penetrating Keratoplasty, often called PK, is the traditional corneal transplant method in which the entire thickness of the cornea is removed and replaced with a donor graft. This procedure is typically indicated for conditions that affect all corneal layers, such as:

• Advanced keratoconus with significant thinning and distortion
• Extensive scarring from infections, injury, or chemical burns
• Corneal dystrophies that affect multiple layers

PK is generally performed under either local or general anesthesia and can take several hours depending on the complexity of the case. Although this method is highly successful—with thousands of procedures performed each year in the United States—it has some drawbacks. Patients will typically have a longer recovery period, often experiencing blurred vision and light sensitivity for several months until the sutures are removed. There is also a higher risk of transplant rejection, where the immune system may attempt to attack the donor tissue.

Selective (Partial-Thickness) Transplants

Over the years, advances in surgical techniques have allowed our cornea specialists to selectively replace only the diseased portions of the cornea. These selective or partial-thickness transplants offer several benefits compared to traditional full-thickness PK, such as faster healing times and lower risks of rejection. The key types of partial transplants include:

Deep Anterior Lamellar Keratoplasty (DALK)

DALK involves replacing the majority of the stroma—the thick middle layer of the cornea—while preserving the patient’s own healthy Descemet’s membrane and endothelial cells. This technique is particularly effective for conditions that exclusively affect the stromal layers, such as:

• Keratoconus, where the cornea becomes cone-shaped due to thinning
• Selective corneal dystrophies affecting the stromal tissue
• Superficial scarring that does not impact the innermost layers

Because the patient’s own endothelium remains intact, DALK carries a lower risk of rejection. In addition, the overall healing process is quicker and the need for long-term use of steroid eye drops is often reduced. However, DALK is a delicate procedure, and in about 10 to 20% of cases, the separation of the stroma from the Descemet’s membrane can be challenging, potentially necessitating conversion to a full-thickness PK.

Descemet’s Stripping Automated Endothelial Keratoplasty (DSAEK)

DSAEK is similar in purpose to DMEK, but the donor tissue includes a thin layer of stroma along with the Descemet’s membrane and endothelial cells. This added tissue makes the graft slightly thicker and, in some ways, easier to manipulate during surgery. However, the extra stromal layer may result in a slightly longer recovery period and a higher risk of postoperative astigmatism. In summary:

• Surgical Ease: The extra tissue can simplify graft handling, especially for surgeons early in their experience.
• Visual Outcomes: Results are generally very good, though on average, vision may not be as sharp as after DMEK.
• Rejection Risk: The risk is marginally higher compared to DMEK because of the additional donor stroma.

While DSAEK is more forgiving during surgery, the added stromal layer can sometimes lead to mild astigmatism and slightly longer visual recovery compared to DMEK.

Descemet’s Membrane Endothelial Keratoplasty (DMEK)

DMEK is a highly refined, minimally invasive procedure that involves transplanting only the donor’s Descemet’s membrane and endothelial cells. One way to think of it is as replacing only the “wallpaper” on the cornea while leaving the structure of the cornea intact. These are the advantages of DMEK:

• Faster visual recovery: Many patients notice improved vision within just a few weeks.
• Excellent visual outcomes: Patients can often achieve near 20/20 vision postoperatively.
• Lower rejection rate: Since very little extra tissue is introduced, the immune system is less likely to reject the graft.
• Smaller incisions: With incisions as small as 2.8 mm, the procedure is less invasive.

Although DMEK is technically challenging, our cornea specialists have developed specialized techniques to manage delicate donor tissue and consistently achieve high surgical success rates.

Corneal Tissue Addition Keratoplasty (CTAK): A Revolutionary Approach

Unlike traditional keratoplasty techniques that involve removing and replacing corneal tissue, CTAK is an additive procedure. This innovative method is designed specifically for keratoconus, a condition where the cornea thins and bulges outward.

How CTAK Works

1. A femtosecond laser creates a precise pocket or channel within the cornea.
2. A custom-shaped, sterile corneal tissue inlay is inserted into the channel to reshape the cornea.
3. The added tissue stabilizes the cornea’s structure and reduces its irregularity, improving vision.

Key Benefits of CTAK

• Preserves the natural cornea – Unlike PK or DALK, CTAK does not remove any corneal layers.
• Minimally invasive – No need for sutures or extended healing time.
• Lower rejection risk – Since the patient’s cornea remains intact, immune rejection is significantly reduced.
• Potential reversibility – Unlike traditional transplants, CTAK inlays can be removed or adjusted if needed.

Emerging Techniques: Descemet Stripping Only (DSO)

For patients with Fuchs’ dystrophy, an alternative to DMEK or DSAEK is Descemet Stripping Only (DSO). Instead of transplanting donor tissue, the damaged Descemet’s membrane is simply removed, allowing healthy cells from the periphery to repopulate the area. While this technique works best in select cases, it offers an even less invasive option for restoring vision.