Limbal Epithelial Transplant

Sangwan et al. first described simple limbal epithelial transplantation (SLET) in 2012; it is a procedure for unilateral limbal stem cell deficiency (LSCD) treatment to restore normal corneal epithelium. SLET involves sectorial harvesting of the limbus from the patient’s healthy contralateral eye to be sectioned into 8-12 smaller limbal autografts. After the removal of any abnormal corneal epithelium and fibrovascular pannus from the diseased eye, an amniotic membrane is placed on the cornea, and the limbal autografts are transplanted onto the membrane followed by a bandage cornea lens.

The amniotic membrane is used because it contains growth factors and possesses antiangiogenic, anti-inflammatory, antimicrobial, and anti-scarring properties that promote the expansion of stem cells and migration of epithelial cells before inflammation and scarring can curtail regeneration.

Allogenic SLET

Allogeneic SLET is similar to autologous SLET except that it uses limbal grafts from cadavers or living donors and may be used to treat bilateral LSCD. Current data has not found a significant difference in outcomes after the use of tissue from either living or cadaveric donors. Allogenic SLET has also been used to achieve rapid surface epithelialization in acute chemical burns.

Patients with allografts from any source require postoperative intravenous immunosuppression followed by long-term systemic immunosuppression, most often cyclosporine, and topical steroid drops to ensure graft survival. When compared to autologous SLET, allogenic SLET has the downside of requiring immunosuppression. Still, it is a treatment for patients who cannot undergo autologous SLET due to bilateral LSCD from a systemic etiology or injury to both eyes.