Visual and refractive outcomes after SMILE versus FS-LASIK: a paired-eye study

Objective: To compare visual acuity, refraction, Schirmer test, tear break-up time (TBUT), esthesiometry, optical quality, higher order aberrations and posterior corneal elevation measurements before and after small-incision lenticule extraction (SMILE) and femtosecond laser-assisted in situ keratomileusis (FS-LASIK).Method: Paired eye, randomized, cohort study.Follow-up was performed at days 1 and 7, and at months 1, 3, 6 and 12. Results: Forty-two eyes were enrolled in the study.Over time, a difference in posterior corneal elevation was statistically significant (p < 0.01) with a greater change in patients treated with SMILE.There was no difference in corrected distance visual acuity and uncorrected distance visual acuity and cylinder between the two techniques; however, there was a statistical significant difference in spherical error and spherical equivalent (p < 0.01).There was no difference between the eyes with FS-LASIK and SMILE in the assessment regarding the TBUT, the Schirmer test and esthesiometry.Conclusions: SMILE showed more changes in the posterior elevation with a progressive backward shift throughout time during follow-up.SMILE and FS-LASIK provides similar results in myopic patients regarding visual acuity, refraction, Schirmer test, TBUT and esthesiometry.