Lamellar Keratoplasty in Keratoconus

Corneal replacement surgery is often required in cases of advanced keratoconus to restore corneal anatomy and improve eyesight. Traditionally, full-thickness penetrating keratoplasty (PKP) has been successfully performed with good long-term outcomes. In the past two decades, lamellar keratoplasty has emerged as an alternate procedure to PKP, with reduced risk of endothelial rejection and better long-term graft survival. Anwar's big bubble (BB) technique of stromal air injection is the most frequently performed deep anterior lamellar keratoplasty (DALK) procedure. The technique allows for the removal of stromal tissue, leaving behind the host pre-Descemet layer (PDL), Descemet membrane (DM), and endothelium, and replacement by donor corneal tissue devoid of DM. Other surgical techniques include viscoelastic assisted dissection, manual near-DM dissection, use of microkeratome or femtosecond laser, and intraoperative anterior segment optical coherence tomography (OCT)-assisted surgery. Smooth interface and minimal residual stromal tissue are essential for optimal visual recovery comparable to that achieved with PKP. Intraoperative and postoperative complications are relatively rare and can be managed easily.