A Partial-Thickness Corneal Transplant

Deep anterior lamellar keratoplasty (DALK) is a partial-thickness corneal transplant procedure that specifically targets the outer layers of the cornea, replacing the damaged stroma while leaving the healthy endothelium and Descemet’s membrane intact. This approach preserves the innermost corneal layer, reducing the risk of rejection and improving overall outcomes compared to full-thickness transplants.

Indications for Deep Anterior Lamellar Keratoplasty

DALK is most suitable for conditions where the damage is confined to the front layers of the cornea, such as:

  • Keratoconus: Particularly advanced cases where the cornea’s shape has become severely irregular, but the endothelium remains functional.
  • Corneal Scarring: Superficial to mid-depth scarring due to trauma, infection, or dystrophic diseases.
  • Stromal Dystrophies: Disorders like granular or lattice dystrophy that affect the corneal stroma but spare the endothelium.

By preserving the endothelial layer, DALK offers a highly effective and safer alternative to full-thickness transplantation in patients whose inner corneal layers are healthy.

Recovery and Healing Timeline

DALK recovery is somewhat similar to penetrating keratoplasty (PK), with stitches often remaining in place for 18 to 24 months to ensure stability. Vision improvement is gradual and may take several months to a year to stabilise. While the initial recovery phase involves some mild discomfort and light sensitivity, the procedure itself is performed under anaesthesia and is generally not painful. The retention of the patient’s endothelium contributes to faster healing compared to PK and reduces long-term complications.

Advantages and Disadvantages of Deep Anterior Lamellar Keratoplasty

Advantages:

  1. Lower Risk of Rejection: Since the endothelium is preserved, there is a significantly lower chance of graft rejection.
  2. Safer for Patients with High Rejection Risk: Ideal for patients who may have a history of previous rejection or autoimmune conditions.
  3. Durable Outcomes: DALK offers long-term visual improvement and can last for decades with proper care.

Disadvantages:

  1. Technically Complex Procedure: DALK requires advanced surgical skills and precision, which may not be available in all centers.
  2. Prolonged Recovery: Vision improvement is gradual, often taking months to years to fully stabilise due to the presence of stitches and postoperative corneal remodeling.
  3. Residual Haze or Irregularity: In some cases, slight optical imperfections may persist, particularly if scarring or stromal irregularities were significant before surgery.

Despite its challenges, DALK is a highly effective and innovative option for patients with anterior corneal diseases, offering the benefits of reduced rejection risk and excellent long-term outcomes.