Feasibility study of treatment of mixed astigmatism with small-incision lenticule extraction (SMILE) by using research software

Purpose: To report the preliminary experience and initial clinical results following SMILE for the treatment of mixed astigmatism. Methods: Thirteen eyes of nine patients with a mean age of 27 +/- 4.36 years were included in the series. In 8/13 eyes, myopic SMILE license and in 4/13 eyes, hyperopic SMILE license (available as part of an open/research software) was used for the treatment. The mean follow-up was 9.5 +/- 8.7 (0.5-24) months, and the median follow-up was 6 months. Setting: Nethradhama Superspeciality Eye Hospital, Bangalore, India. Design: Exploratory study. Results: The mean preoperative sphere, cylinder, and spherical equivalent (SE) were 1.44 +/- 1.63, -2.70 +/- 2.30, and -0.24 +/- 1.14 D, which changed to -0.03 +/- 0.30, -0.28 +/- 0.48, and -0.18 +/- 0.49 D, respectively, 6 months postoperatively. Furthermore, 85% (11/13) eyes were within +/- 0.50 D, 92% (12/13) eyes were within +/- 1.00 D, while all eyes were within +/- 1.50 D of SE correction. All eyes were within +/- 1.00 D of cylinder correction. In addition, 92% (12/13) eyes had UDVA better than 20/32, with 54% (7/13) eyes having UDVA 20/20 or better. Safety and efficacy indices were 1.08 and 0.92, respectively. No eyes lost more than 1 line of CDVA. The mean corneal higher order aberrations (HOA) increased from 0.111 +/- 0.048 to 0.209 +/- 0.056 (P < 0.001). The mean objective scatter index (OSI) did not show a significant change (pre = 0.71 +/- 0.69, 6 months = 0.89 +/- 0.20; P = 0.35). Conclusion: Early experience showed that SMILE was feasible for the management of eyes with mixed astigmatism, without any intraoperative complications, unique to the procedure.