Microkeratome versus femtosecond laser predissection of corneal grafts for anterior and posterior lamellar keratoplasty

Purpose: To compare 2 different techniques for predissection of human anterior and posterior lamellar corneal grafts for eye bank storage. Methods: A mechanical microkeratome (group 1, N = 5) and a femtosecond laser (group 2, N = 5) were used to dissect intended 350-mu m-deep lamellar planes in deepithelialized donor corneas mounted on an artificial anterior chamber. These corneas were replaced in Optisol GS at 4 degrees C postoperatively and examined 2 days later to simulate a clinical scenario. Ultrasonic pachymetry of corneal lamellar sections was measured before and after separation of the lamellar grafts. Group 1 sections were separated by the mechanical microkeratome, whereas group 2 sections were manually separated 2 days after laser dissection. Endothelial cell viability was evaluated in posterior grafts. Results: Total corneal thicknesses immediately before dissection were 559 +/- 61 (group 1) and 578 +/- 79 mu m (group 2; P = 0.46). Immediate postdissection anterior and posterior graft thicknesses were 361 +/- 68 and 203 +/- 74 mu m (group 1), respectively. Achieved anterior and posterior graft thicknesses 2 days later were 282 +/- 44 and 413 +/- 35 mu m (group 1) and 324 +/- 112 and 397 +/- 51 mu m (group 2), respectively. Percentage of devitalized endothelial cells were 3.4% +/- 1.6% (group 1) and 1.6% +/- 1.2% (group 2; P = 0.35). Conclusions: Centralized predissection by both techniques, cold storage, and shipping by airmail results in viable grafts without significant endothelial cell loss 2 days later.