To evaluate the refractive outcomes of small incision lenticule extraction (SMILE) in high myopia patients compared with mild to moderate myopia patients.

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, <-6.0 D) and high myopia (B group, ≥-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.

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).

This study showed that SMILE is effective and safe for correcting high myopia as well as mild to moderate myopia.