Limbal allografting using FK-506

Editor,—While we agree with Dua and Azuara-Blanco1 that the use of “fresh” donor eyes for limbal transplantation is preferable, social and surgery scheduling limitations may force surgeons to use stored corneoscleral (C-S) rims. Tsubota et al  2 have demonstrated the viability of limbal stem cells (SCs) harvested from C-S rims stored in Optisol GS for up to 5 days. The surgical method described by Dua and Azuara-Blanco1 positions the limbal allograft posterior to the anatomical limbus in the host. The 150 μm thick donor limbal graft can result in a stepped ocular surface, which can be detrimental to long term survival of the transplanted epithelium. Splitting the ring of limbal tissue and interposing a separate piece of corneal stroma or limbus theoretically allows chinks in the reconstituted limbal barrier. Finally, the technique described does not allow sufficient flexibility in titrating the thickness of the donor tissue used. Since an important goal of ocular surface reconstruction is to achieve a smooth surface, surgeons often have to use donor limbal grafts of differing thickness in individual recipient eyes. This flexibility is possible if the limbal graft is fashioned from a C-S rim. In eyes undergoing combined penetrating keratoplasty and limbal transplantation, apposing the donor limbal and corneal graft without an intervening gap is preferable. The …