EVALUATION OF ENDOTHELIAL-CELL CHANGES 1-YEAR AFTER EXCIMER-LASER IN-SITU KERATOMILEUSIS

Objective: To investigate changes in the human corneal endothelium aft er excimer laser in situ keratomileusis for the correction of high myo pia. Methods: Preoperative and serial postoperative specular microscop y of the central corneal endothelium was performed on 31 patients (45 eyes) (group A) who underwent laser in situ keratomileusis for the cor rection of myopia ranging from -8.25 to -18.50 diopters. Twenty-one pa tients (30 eyes) were contact lens wearers (group B), and 10 patients (15 eyes) had never worn contact lenses (group C). The central endothe lium was analyzed for cell density, coefficient of variation in cell s ize, and hexagonality. The preoperative data were compared with those obtained 3, 6, and 12 months after surgery in all groups. Results: In group A, the postoperative mean cell density increased significantly ( 2.3%) at 6- month follow-up (P=.04); the coefficient of variation decr eased at all follow-ups (P<.001); and the percentage of hexagonal cell s increased at all follow-ups (P<.05). In group B, there was a signifi cant postoperative increase in cell density at the 3- (2.36%) and 6-mo nth (3.74%) follow-ups (P<.05); the coefficient of variation decreased at all follow-ups (P<.001); and the hexagonality was also significant ly higher at all follow-ups than it was before treatment (P<.05). In g roup C, no significant differences in mean cell density or morphometri c indexes were found between preoperative and postoperative values. Co nclusions: Laser in situ keratomileusis caused no damage to the centra l corneal endothelium. The postoperative improvements in endothelial c ell density and morphometric indexes are related to postoperative disc ontinuation of contact lens use.