Evaluation of endothelial cell changes 1 year after excimer laser in situ keratomileusis

Objective: To investigate changes in the human corneal endothelium after excimer laser in situ keratomileusis for the correction of high myopia. Methods: Preoperative and serial postoperative specular microscopy of the central corneal endothelium was performed on 31 patients (45 eyes) (group A) who underwent laser in situ keratomileusis for the correction of myopia ranging from -8.25 to -18.50 diopters. Twenty-one patients (30 eyes) were contact lens wearers (group B), and 10 patients (15 eyes) had never worn contact lenses (group C). The central endothelium was analyzed for cell density, coefficient of variation in cell size, 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 decreased at all follow-ups (P<.001); and the percentage of hexagonal cells increased at all follow-ups (P<.05). In group B, there was a significant postoperative increase in cell density at the 3- (2.36%) and 6-month (3.74%) follow-ups (P<.05); the coefficient of variation decreased at all follow-ups (P<.001); and the hexagonality was also significantly higher at all follow-ups than it was before treatment (P<.05). In group C, no significant differences in mean cell density or morphometric indexes were found between preoperative and postoperative values. Conclusions: Laser in situ keratomileusis caused no damage to the central corneal endothelium. The postoperative improvements in endothelial cell density and morphometric indexes are related to postoperative discontinuation of contact lens use.