Predictability and stability of laser-assisted subepithelial keratectomy with mitomycin C for the correction of high myopia

Abstract

The purpose of this study was to evaluate the predictability and stability of laser-assisted subepithelial keratectomy (LASEK) with mitomycin C (MMC) in correction of high myopia (≤-6.0 diopters [D]) as compared to low-to-moderate myopia (>-6.0D). This is a retrospective, comparative, cohort study which included 43 eyes of 43 consecutive patients who underwent LASEK with MMC in a private hospital in Hong Kong by a single surgeon. Twenty-five eyes had high myopia (mean spherical equivalent [SE] = -8.53±1.82D) and 18 eyes had low-to-moderate myopia (mean SE = -3.99±1.37D) before surgery. In terms of refractive predictability, mean SE was significantly better in eyes with preoperative low-to-moderate myopia than high myopia at 6 months (0.04±0.23 vs 0.31±0.52D, P=.035). In terms of refractive stability, between 1 and 3 months, both groups had mean absolute change of SE of around 0.25D. Between 3 and 6 months, preoperative low-to-moderate myopia group had significantly less absolute change of SE compared to high myopia group (0.07 vs 0.23D, P=.003). More eyes with preoperative high myopia changed SE by more than 0.25D than those with low-to-moderate myopia between 3 and 6 months (32.0% vs 5.6%, P=.057). In conclusion, LASEK with MMC is more unpredictable and unstable in correction of high myopia than low-to-moderate myopia. The refractive outcome of most low-to-moderate myopia correction stabilizes at 3 months. Stability is not achieved until after 6 months in high myopia correction.