SMILE Procedures With Four Different Cap Thicknesses for the Correction of Myopia and Myopic Astigmatism

PURPOSE: To study the feasibility of performing myopic femtosecond small incision lenticule extraction (SMILE) with four different cap thicknesses (130, 140, 150, and 160 μm). METHODS: In this retrospective, comparative, non-randomized clinical trial, a refractive lenticule of intrastromal corneal tissue was cut with the VisuMax femtosecond laser system (Carl Zeiss Meditec AG, Jena, Germany) using different depths of the non-refractive lenticule cut. Manifest refraction, uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and Objective Scattering Index (OSI) were evaluated. Minimum follow-up time was 1 year. RESULTS: Ninety-four eyes of 47 patients with myopia with (14 patients) and without (33 patients) astigmatism were treated. One year after the surgery, mean log-MAR UDVA, logMAR CDVA, SE, and OSI were 0.07 ± 0.12, 0.01 ± 0.37, 0.07 ± 0.57, and 0.88 ± 0.17, respectively (P < .05). There were no significant statistical differences in logMAR UDVA, logMAR CDVA, SE, or OSI (P > .05) variables when the different groups were compared for the same periods of time. CONCLUSIONS: No differences in visual acuity, refractive outcomes in optical visual quality, or complications were observed when using SMILE at four different depths.