Dalk

Deep anterior lamellar keratoplasty (DALK) is a corneal transplant procedure that replaces diseased anterior corneal stroma while preserving the recipient’s Descemet’s membrane and endothelium. By retaining the host endothelium, DALK reduces the risk of endothelial graft rejection and preserves natural endothelial function.

In DALK, a plane is created between the stroma and Descemet’s membrane, after which the diseased anterior stroma is removed and replaced with donor anterior stroma. Common techniques include the big-bubble method, where air is injected to separate stroma from Descemet’s membrane, and manual dissection with microinstruments. Variants may use viscoelastic or laser-assisted steps to aid dissection. If Descemet’s membrane is breached, the procedure may need to be converted to a full-thickness transplant or managed as an anterior lamellar keratoplasty.

Indications for DALK include keratoconus, stromal dystrophies (such as granular or lattice dystrophy), and corneal scarring where the endothelium is healthy and endothelial function is preserved. It is often chosen to avoid endothelial rejection risks, particularly in young patients or when endothelial pathology is absent.

Advantages of DALK consist of a lower risk of endothelial graft rejection, avoidance of endothelial graft failure, and preservation of host endothelium. Limitations include technical complexity, a steeper learning curve, and potential intraoperative Descemet’s membrane perforation, which may necessitate conversion to penetrating keratoplasty or other techniques. Postoperative management focuses on suture adjustment and refractive normalization, with visual rehabilitation often achieving good outcomes in appropriately selected cases.