Corneal biomechanics after small-incision lenticule extraction versus Q-value–guided femtosecond laser-assisted in situ keratomileusis

PURPOSE: The aim of this study was to compare the changes in corneal biomechanical properties following small-incision lenticule extraction (SMILE) versus Q-value–guided femtosecond laser-assisted in situ keratomileusis (Q-FS-LASIK). METHODS: In this prospective comparative study, patients with a sphere plus cylinder measurement of less than −10.00 D and cylinder measurement of less than −5.00 D were included in the study. A total of 160 patients (160 eyes) with myopia and myopic astigmatism were divided into the two groups, with 80 patients (80 eyes) allocated to SMILE and 80 patients (80 eyes) allocated to Q-FS-LASIK. Corneal hysteresis (CH) and the corneal resistance factor (CRF) were quantitatively assessed using the Ocular Response Analyzer (ORA) preoperatively and at 1 day, 2 weeks, and 1 and 3 months postoperatively. RESULTS: Both types of surgery were associated with statistically significant decreases in CH and the CRF at postoperative day 1 (both P < 0.01). In both groups, the decreases subsequently stabilized with no further deteriorations compared to postoperative day 1 (P > 0.05). Both groups showed similar biomechanical changes at each time point (all P > 0.05). CONCLUSIONS: Both SMILE and Q-FS-LASIK resulted in a decrease in CH and the CRF at postoperative 1 day, with the decreases stabilizing after this point. There were no significant differences between the short term effects of SMILE and Q-FS-LASIK on corneal biomechanical properties.