Re-Evaluation of the Safety of Laser-Assisted Subepithelial Keratectomy

Purpose: Additional analyses of outcomes of laser-assisted subepithelial keratectomy (LASEK) are still necessary to improve the safety of LASEK. Therefore, in our study, outcomes were assessed retrospectively in 561 eyes that underwent LASEK treatment. Methods: Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA) and residual spherical equivalent were analyzed at 3 and 6 months postoperatively. We assessed four subgroups based on the degree of preoperative myopia considering mean BSCVA and loss of two or more lines. Results: Mean UCVAs and BSCVAs were obtained at 3 and 6 months postoperatively (1.23/1.35 and 1.23/1.37, respectively). The mean predictability was within ±0.125 diopters. Conversely, the safety indexes were 0.94 and 0.96 respectively, and the efficacy indexes were 0.86 and 0.86 at 3 and 6 months postoperatively, respectively. 8.4% eyes and 5.2% eyes lost two or more lines of BSCVA at 3 and 6 months postoperatively, respectively. The mean BSCVAs of the high or ultra-high groups were significantly lower than those of the low or mild groups both 3 months and 6 months postoperatively. The incidence rates of losing two or more lines of BSCVA in the high or ultra-high myopia groups were significantly greater than in the low or mild groups at 3 months and 6 months postoperatively. Conclusion: LASEK predictably corrected myopia achieving >1.2 in UCVA and BSCVA. However, the safety and efficacy indexes were <1.0, which were related to the loss of two or more lines of BSCVA. Since the incidence rates of losing two or more lines of BSCVA were greater in the high or ultra-high myopia groups, we consider LASEK as more safely performed in patients with low to mild preoperative myopia.