Corneal endothelial changes after laser in situ keratomileusis

Purpose: To ascertain whether 193 nm excimer laser in situ keratomileusis (LASIK) to correct high myopia causes in vivo changes in the human corneal endothelium 3 and 6 months after surgery. Setting: Alicante Institute of Ophthalmology, University of Alicante, Spain. Methods: Preoperative and serial postoperative specular microscopy of the central corneal endothelium was done in 33 eyes of 19 patients (Group I)with a mean age of 34.3 years +/- 10.6 (SD) (range 20 to 60 years) who had LASIK to correct myopia of between 8.25 and 18.50 diopters (D) (mean 11.90 +/- 2.20 D). Twelve patients (20 eyes) were contact lens wearers (Group 2), and 7 (13 eyes) had never worn contact lenses (Group 3). The central endothelium was analyzed for several parameters including cell density, coefficient of variation in cell size, and hexagonality. The data obtained before surgery were compared with those obtained after surgery in all groups. Results: There was no significant difference in age, sex, and preoperative myopia between Groups 2 and 3. In Group 1, mean cell density was significantly higher (3.5%) 6 months after surgery (P = .017) and the coefficient of variation decreased 3 and 6 months after surgery (P < .001); no significant changes were noted in the percentage of hexagonal cells. In Group 2, there was a significant increase in cell density (4.8%) 6 months after surgery (P = .010) and the coefficient of variation decreased at 3 and 6 months after surgery (P < .001); the hexagonality did not change postoperatively. In Group 3, there were no significant differences between preoperative and postoperative mean cell density, coefficient of variation, or hexagonality. Conclusion: Laser in situ keratomileusis caused no damage to the central corneal endothelium. Postoperative improvements in the endothelial cell density and the coefficient of variation in cell size values were related to the discontinuance of contact lens use after surgery.