Recent advances in corneal transplantation for keratoconus

From the rise of modern corneal graft surgery in the late 1950s until recently, corneal transplantation for keratoconus almost exclusively consisted of a full-thickness transplant, termed penetrating keratoplasty. This technique involved the removal of all of the layers of the patient's central cornea and replacement with a full-thickness graft. Over approximately the past 20 years, a quiet revolution has occurred with the development of several other types of corneal transplantation surgery for keratoconus. In addition to full thickness grafts, several different types of partial thickness, lamellar grafts, have been developed and are viable alternatives to a full-thickness graft in selected patients. The main aim of these lamellar grafts is to selectively replace the corneal stroma, leaving intact the patient's own Desçemet's membrane and endothelial cells, the main target of allograft transplant rejection. In this article, we review the current options with regard to corneal transplantation for keratoconus and review the evidence comparing newer and more established techniques.