Purpose: To report long-term visual and refractive results of small-incision lenticule extraction (SMILE) in treatment of high myopia.
Materials and methods: Medical records of patients who underwent SMILE for surgical correction of myopia or myopic astigmatism were retrospectively reviewed. Only patients with a preoperative spherical equivalent of subjective manifest refraction (SE) ≥ 6 D and a postoperative follow-up of 5 years were included in the study. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and SE were analyzed preoperatively and at 1-, 3-, and 5-year postoperative periods.
Results: Thirty-seven eyes of 37 patients were included in the study. The mean attempted SE was -7.47 ± 1.10 D (range -6.00 to -10.00 D). At the 5-year visit, the mean difference between achieved and attempted SE was -0.43 ± 0.47 (0.50 to -1.25 D). Mean postoperative UDVA and CDVA were 0.20 ± 0.18 and 0.06 ± 0.08 logMAR, respectively. At the 1-year visit, 70% and 97% of the eyes were within ±0.50 D and ±1.00 D of the intended correction. At the 5-year follow-up, 59% and 92% percent of the eyes were within ±0.50 D and ±1.00 D of the intended SE, respectively. At the 5-year visit, the efficacy index was 0.89 ± 0.26 and the safety index was 1.16 ± 0.20. Fifty-four percent of the eyes gained one or more lines of CDVA.
Conclusion: SMILE with an intended correction of up to a spherical equivalent of 10 D is safe and effective. However, there is regression of the refractive effect over extended follow-up.