Outcomes of Small Incision Lenticule Extraction: Mild to Moderate Myopia versus High Myopia

ABSTRACT

PURPOSE: To evaluate the refractive outcomes of small incision lenticule extraction (SMILE) in high myopia patients compared with mild to moderate myopia patients. METHODS: This study included 332 eyes of 166 myopic patients treated with SMILE using Visumax 500 kHz femtosecond laser. Treated eyes were divided into 2 groups according to preoperative spherical equivalent (SE) mild to moderate myopia (A group, or =-6.0 D). Follow-up visits were at 1 day, 1 week, 1 month, 3 months, and 6 months. The outcome measures included uncorrected distance visual acuity (UDVA), best corrected distance visual acuity (BDVA), postoperative SE, efficacy index, safety index and predictability. RESULTS: Preoperative SE was -4.85 +/- 0.86 D in the A group and -7.70 +/- 1.0 D in the B group. No differences were observed between -0.04 +/- 0.29 D in the A group and -0.30 +/- 0.37 D in the B group at 6 months postoperatively (p = 0.062). At 6 months postoperatively, 98.3% and 97.3% had UDVA of 20/25 or better in the A group and B group, respectively. In the A group, 97.3% and 100% were within +/-0.5 D and +/-1.0 D of intended correction and in the B group, 91.7% and 96.9% were within +/-0.5 D and +/-1.0 D, respectively. Efficacy indices were 1.02 +/- 0.19 in the A group and 0.99 +/- 0.18 in the B group. Safety indices were 1.16 +/- 0.16 in the A group and 1.14 +/- 0.16 in the B group. The efficacy and safety indices were not significantly different between the A and B groups at 6 months postoperatively (p = 0.09, p = 0.695, respectively). CONCLUSIONS: This study showed that SMILE is effective and safe for correcting high myopia as well as mild to moderate myopia.