When managing advanced keratoconus, corneal dystrophies, or corneal sczrring, surgical options such as penetrating keratoplasty (PK) or deep anterior lamellar keratoplasty (DALK) may be considered. While both procedures replace damaged corneal tissue, they differ in the layers treated and the associated risks.

Penetrating Keratoplasty (PK) is a full-thickness corneal transplant. In this procedure, all layers of the diseased cornea, including the innermost endothelium, are replaced with donor tissue. In the diagrams, this is represented by a blue line marking the endothelial layer. During PK, the blue line is replaced, meaning the new cornea includes a donor endothelium. While effective, PK comes with a higher risk of graft rejection since the immune system may target the donor endothelium.

In contrast, Deep Anterior Lamellar Keratoplasty (DALK) preserves the host endothelium. During DALK, only the damaged outer and middle layers of the cornea are replaced, leaving the host’s endothelial layer (the blue line in the diagram) intact. This preservation is significant because it greatly reduces the risk of rejection, as the host’s endothelium is not recognized as foreign tissue.

Additionally, DALK procedures are particularly beneficial for conditions like keratoconus or specific corneal dystrophies that leave the endothelium unaffected. By retaining the native endothelium, DALK minimizes the need for long-term immunosuppression, enhancing patient outcomes and recovery.

Both procedures are highly specialized, and the choice between them depends on the patient’s condition and the health of their corneal layers. Understanding these distinctions can empower patients to make informed decisions about their care. If you’re considering treatment for keratoconus or a corneal dystrophy, consult with an ophthalmologist to discuss the best option for your needs.

Dr. Cronin is proud to be one of the very few surgeons in the country who have access to the Ziemer Z8 femtosecond laser which can assist in achieving a deep anterior lamellar procedure for a significantly higher percentage of cases than traditional manual techniques can achieve.