PURPOSE: To compare the corneal biomechanical properties before and after small incision lenticule extraction (SMILE) and femtosecond laser-assisted LASIK in different levels of myopia with the Ocular Response Analyzer (Reichert Ophthalmic Instruments, Depew, NY). METHODS: A total of 187 and 79 eyes that received SMILE or LASIK, respectively, between January and June 2013 at Zhongshan Ophthalmic Center were enrolled in this study. Patients were grouped according to surgery type (SMILE or LASIK) and -6.00 diopters (D) or less (≤ -6.00 D) or myopia greater than -6.00 D (> -6.00 D). Corneal hysteresis, corneal resistance factor, and 37 waveform parameters were recorded and compared preoperatively and at 1 week and 1 and 3 months postoperatively. RESULTS: There was a significant decrease of corneal hysteresis, corneal resistance factor, p1area, and p2area, and an increase of path1 and path2 in both SMILE and LASIK. In myopia -6.00 D or less, the differences between SMILE and LASIK were not significant (P > .05), but in myopia greater than -6.00 D, the corneal hysteresis, corneal resistance factor, p1area, and p2area decreased significantly more in LASIK than in SMILE (P < .05). CONCLUSIONS: When comparing SMILE with LASIK, myopia was greater than -6.00 D, and the corneal hysteresis, corneal resistance factor, p1area, and p2area decrease was less after SMILE.
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