AIM:To investigate the clinical safety, efficacy, predictability and stability of small incision lenticule extraction(SMILE)for the correction of myopia and astigmatism.

METHODS: This was a prospective clinical controlled study involved 547 patients(1080 eyes)with myopia and astigmatism. Out of these, 560 eyes of 285 patients were treated with SMILE and 520 eyes of 262 patients were treated with femtosecond laser assisted laser in situ keratomileusis(FS-LASIK). The patients were followed up 12mo after operation and received ophthalmologic examinations including uncorrected visual acuity(UCVA), best corrected visual acuity(BCVA), manifest refraction, slitlamp examination and corneal topography at 1d,1wk and 1,6 and 12mo. The value of decentration from pupil center was measured at 3mo.

RESULTS: The UCVA at 1d, 1wk, 1, 6 and 12mo were respectively 0.029±0.13 LogMAR, 0.001±0.11LogMAR,-0.019±0.11 LogMAR, -0.020±0.08 LogMAR, -0.011±0.10 LogMAR in SMILE group, and -0.017±0.08 LogMAR, -0.019±0.09 LogMAR, -0.031±0.10 LogMAR, -0.024±0.09 LogMAR, -0.002±0.12 LogMAR in FS-LASIK group. The UCVA in SMILE group were significantly lower than that in FS-LASIK group at 1d and 1wk(P<0.05), while no difference were observed at other time points. The spherical equivalent(SE)at 1,6 and 12mo were respectively -0.03±0.29D, -0.04±0.28D,-0.06±0.32D in SMILE group, and 0.02±0.20D,-0.01±0.29D,-0.08±0.33D in FS-LASIK group, and the difference was statistically significant at 1mo(P<0.05), except other time points. At 3mo, the mean decentration from pupil center were 0.21±0.11mm for SMILE group and 0.20±0.08mm for FS-LASIK group, there was no significant difference between the two groups(P>0.05).

CONCLUSION: SMILE is effective, predictable, stable and safe for myopia and astigmatism. However, SMILE showed slower vision recovery compared with FS-LASIK in the early postoperative period.