To assess the effects of laser in situ keratomileusis (LASIK) on the corneal endothelium.

In a prospective study, the corneal endothelium of 98 eyes of 65 consecutive patients (mean age, 41 years; range, 22 to 66 years) was photographed before, 2 weeks after, and 12 weeks after LASIK for the correction of 2.75 to 14.5 diopters of myopia. Theoretical ablation depths were 200 to 330 μm below the corneal surface. Cell density, coefficient of variation, and percent of hexagonal cells were determined using 150 to 200 cells from each image. Eighty-eight eyes (91%) of 59 patients had a history of contact lens wear.

The mean ± SD preoperative endothelial cell density was 2,549 ± 365 cells per mm², and the mean coefficient of variation was 0.35 ± 0.06. There was no statistically significant change in the mean endothelial cell density or mean coefficient of variation of cell size at the 2-week (2,561 ± 360 cells per mm² and 0.35 ± 0.06) or 12-week (2,541 ± 364 cells per mm² and 0.35 ± 0.05) postoperative examinations. The percent of hexagonal cells was not significantly changed 2 weeks postoperatively; however, 12 weeks postoperatively (P =.0413, two-tailed t test), the percent of hexagonal cells was decreased by 1%.

Corneal endothelial cell density and morphology were unchanged 2 and 12 weeks after LASIK for the correction of up to 14.5 diopters of myopia. In this LASIK study, the correction of up to 14.5 diopters of myopia appears to cause no clinically significant effect on corneal endothelial cell density or morphology.