Refractive outcomes comparing small-incision lenticule extraction and femtosecond laser–assisted laser in situ keratomileusis for high myopia

Purpose: To compare the long-term refractive effects of small-incision lenticule extraction (SMILE) and femtosecond laser–assisted laser in situ keratomileusis (FS-LASIK) on the correction of high myopia and astigmatism. Setting: The Eye and ENT Hospital of Fudan University, Shanghai, China. Design: Retrospective case series. Methods: Patients had SMILE or FS-LASIK for high myopia. Subgroup analyses of high myopia (–6.00 to –8.75 diopters [D]) and extremely high myopia (≥–9.00 D) were performed. The main outcome measure was refractive predictability, compared between SMILE and FS-LASIK groups. Secondary outcomes included efficacy, safety, and residual astigmatism. Results: This study included 121 patients (121 eyes: 75 in the SMILE group and 46 in the FS-LASIK group). No differences were found in terms of refractive predictability between SMILE and FS-LASIK in eyes with high myopia: 56% vs 58.7% achieved ± 0.50 D of attempted correction ( P = .771) and 81.3% vs 76.1% achieved ± 1.00 D of attempted correction ( P = .489). Efficacy indices of the SMILE and FS-LASIK groups were 1.02 ± 0.24 and 1.03 ± 0.24 ( P = .742), respectively; safety indices were 1.23 ± 0.22 and 1.20 ± 0.24 ( P = .324), respectively. Logarithm of the minimum angle of resolution uncorrected distance visual acuity and spherical equivalent in the high myopia subgroup were better than in the extremely high myopia subgroup after both SMILE and FS-LASIK ( P < .01). Conclusions: SMILE and FS-LASIK were both effective in correcting high myopia and myopic astigmatism. However, both techniques may require further nomogram adjustments when treating eyes with extremely high myopia.