Contemporary limbal stem cell transplantation - a review

Conjunctivalization of the cornea is the hallmark of limbal stem cell deficiency (LSCD). This is often associated with persistent corneal epithelial defects and a fibrovascular pannus. LSCD can be unilateral or bilateral and partial or total. In partial LSCD involving the visual axis sequential sector conjunctival epitheliectomy (SSCE) is a useful option. In total LSCD, transplantation of limbal tissue or of ex vivo expanded sheets is the mainstay. In unilateral cases autolimbal transplant is the procedure of choice. In bilateral cases living (related) and cadaver donors are considered. The former has the advantage of being fresh and can be human leucocyte antigen matched. Procedures for harvesting limbal tissue from living donors are identical. Different strategies are required for harvesting tissue from cadaver whole globes or sclero-corneal rims. Recipient eye preparation requires removal of the fibrovascular tissue. Donor explants are generally sutured directly on the denuded recipient surface without the preparation of a 'bed' to fit the explant. It is imperative that inflammation is meticulously controlled before limbal transplantation especially if tissue from living donors is used. Limbal transplantation, with the exception of a corneal graft, should be the last surgical intervention planned. Meticulous postoperative care and treatment with antibiotics, steroids, artificial tears and autologous serum are required. With allografts long-term immunosuppression is necessary. Limbal transplantation is contraindicated in the presence of severe dry eye. Despite its complexities limbal transplantation does significantly improve vision related quality of life. Autografts give the best results and living related donor grafts are next best. Majority of cadaver grafts fail in 5 years.