PURPOSE: To compare the visual results, higher-order aberrations, and corneal biomechanical properties of femtosecond small incision lenticule extraction (SMILE) at depths of 100 and 160 μm. METHODS: A prospective comparative interventional clinical trial of a series of patients who underwent SMILE. In the right eye, a refractive lenticule was created at a depth of 100 μm, and in the left eye, a depth of 160 μm was used. Manifest refraction, uncorrected visual acuity, total high-order aberrations (THOA), and corneal biomechanical properties of both eyes were evaluated 1 month postoperatively. RESULTS: Thirty patients with bilaterally stable refractive errors were included in this study. One month postoperatively, mean corneal hysteresis was 9.71 ± 0.68 in the right eyes and 9.97 ± 0.77 in the left eyes, whereas the mean corneal resistant factor was 9.13 ± 1.04 and 9.31 ± 0.92 in the right and left eyes, respectively. Both corneal hysteresis and corneal resistant factor showed statistically significantly higher values in the left eyes (lenticule at a depth of 160 μm). No statistically significant differences were found between the right and the left eyes regarding manifest refraction, uncorrected visual acuity, and THOA. CONCLUSIONS: Creating the refractive lenticule at a depth of 160 μm in SMILE had less effect on the corneal biomechanics than did creating a lenticule at a depth of 100 μm with no statistically significant differences in the refractive outcome and THOA between both groups.
PURPOSE: To compare the visual results, higher-order aberrations, and corneal biomechanical properties of femtosecond small incision lenticule extraction (SMILE) at depths of 100 and 160 μm. METHODS: A prospective comparative interventional clinical trial of a series of patients who underwent SMILE. In the right eye, a refractive lenticule was created at a depth of 100 μm, and in the left eye, a depth of 160 μm was used. Manifest refraction, uncorrected visual acuity, total high-order aberrations (THOA), and corneal biomechanical properties of both eyes were evaluated 1 month postoperatively. RESULTS: Thirty patients with bilaterally stable refractive errors were included in this study. One month postoperatively, mean corneal hysteresis was 9.71 ± 0.68 in the right eyes and 9.97 ± 0.77 in the left eyes, whereas the mean corneal resistant factor was 9.13 ± 1.04 and 9.31 ± 0.92 in the right and left eyes, respectively. Both corneal hysteresis and corneal resistant factor showed statistically significantly higher values in the left eyes (lenticule at a depth of 160 μm). No statistically significant differences were found between the right and the left eyes regarding manifest refraction, uncorrected visual acuity, and THOA. CONCLUSIONS: Creating the refractive lenticule at a depth of 160 μm in SMILE had less effect on the corneal biomechanics than did creating a lenticule at a depth of 100 μm with no statistically significant differences in the refractive outcome and THOA between both groups.