One-year outcomes of small-incision lenticule extraction (SMILE): mild to moderate myopia vs. high myopia

Jae Ryun Kim, Bu Ki Kim, Su Joung Mun, Young Taek Chung, Hyun Seung Kim

The purpose of this study was to compare the refractive outcomes of small incision lenticule extraction (SMILE) in high-myopic patients with those of mild- to moderate-myopic patients. This study included 183 eyes of 92 myopic patients treated with SMILE using a VisuMax 500-kHz femtosecond laser. Treated eyes were divided into two groups, according to the preoperative spherical equivalent (SE): mild to moderate myopia (A group, <-6.0 D) and high myopia (B group, ≥ - 6.0 D). Follow-up visits were at 1 day, 1 week, and 1, 3, 6, and 12 months. The outcome measures included uncorrected distance visual acuity (UDVA), best-corrected distance visual acuity (BDVA), postoperative SE, efficacy index, safety index, and predictability. Preoperative SE was -5.05 ± 0.71 D in the A group and -7.67 ± 1.01 D in the B group. No differences were observed between -0.13 ± 0.38 D in the A group and -0.24 ± 0.35 D in the B group 12 months postoperatively (p = 0.18). At 12 months postoperatively, 93.1 % and 76.8 % had an UDVA of 20/20 or better in the A and B groups, respectively. In the A group, 87.9 % and 96.6 % were within ±0.5 D and ±1.0 D, respectively, of the intended correction; in the B group, 88.0 % and 97.6 % were within ±0.5 D and ±1.0 D, respectively. The efficacy index was 1.04 ± 0.19 in the A group and 0.99 ± 0.19 in the B group. The safety index was 1.27 ± 0.17 for the A group and 1.24 ± 0.17 for the B group. The efficacy and safety index were not significantly different between the two groups 12 months postoperatively (p = 0.141 and p = 0.307, respectively). This study showed that SMILE is effective and safe for correcting high myopia, as well as mild to moderate myopia.