Randomized Clinical Trial Comparing Femtosecond LASIK and Small-Incision Lenticule Extraction

Abstract

Purpose: To compare femtosecond LASIK with small-incision lenticule extraction (SMILE) for the treatment of myopia and myopic astigmatism.

Design: Prospective, randomized, paired-eye, single-masked clinical trial.

Participants: Consecutive eligible patients were randomized to undergo SMILE and LASIK in either eye at a single tertiary referral eye center.

Methods: Patients were treated in each eye using the VisuMax (Carl Zeiss Meditec, Jena, Germany) 500-kHz femtosecond laser system. Excimer ablation was subsequently performed using the WaveLight EX500 excimer laser (Alcon Laboratories, Inc, Fort Worth, TX) in the eye for LASIK.

Main outcome measure: Refractive predictability at 3 months. Secondary outcomes were refractive outcomes, that is, efficacy and safety at 3 and 12 months.

Results: We recruited 70 consecutive patients (mean age, 28±5 years; 64% women; all Asian) with no difference in preoperative spherical equivalent (SE) between eyes (-5.3±1.8 diopters [D] vs. -5.2±1.7 D; P = 0.87). At 3 months, 99% of SMILE eyes and 97% of LASIK eyes achieved SE within ±1.0 D of attempted correction (P = 1.0). Small-incision lenticule extraction achieved similar results as LASIK in terms of efficacy index (0.97±0.20 vs. 0.99±0.20; P = 0.56), uncorrected distance visual acuity (UDVA) of 20/40 or better (100% vs. 100%; P = 1.0), and UDVA of 20/20 or better (84% vs. 87%; P = 0.63). Safety index (1.1±0.2 vs. 1.1±0.2; P = 0.57) was similar between SMILE and LASIK eyes at 3 months. At 12 months, SMILE was similar to LASIK in terms of efficacy (85% vs. 83% UDVA ≥20/20; P = 0.81), predictability (99% vs. 99% ±1.0 D of attempted correction SE; P = 1.0), and safety (1.15±0.20 vs. 1.15±0.20; P = 0.93).

Conclusions: The results from this randomized trial suggest that SMILE produced promising refractive outcomes in terms of predictability, efficacy, and safety at 3 and 12 months of follow-up.