Microdistortions in Bowman's Layer 3 Years After SMILE for Myopia.

Abstract

To investigate the characteristics and changes in microdistortions in Bowman's layer 3 years after small incision lenticule extraction (SMILE). In this non-randomized, prospective study, 50 eyes of 28 patients who received SMILE with a mean spherical equivalent of -6.72 ± 1.41 diopters (D) were divided into a thin lenticule group (lenticule thickness ⩽ 135 µm) and a thick lenticule group (lenticule thickness > 135 µm). Examinations were performed preoperatively and 1 day, 1 month, and 3 years after SMILE. Microdistortions in Bowman's layer determined via optical coherence tomography were analyzed digitally. All patients completed the follow-up with no complications. Three years after SMILE, no eyes exhibited loss of corrected distance visual acuity. The safety index was 1.20 ± 0.15 and the efficacy index was 1.01 ± 0.10. The respective mean lengths of microdistortions at 1 day, 1 month, and 3 years after SMILE were 2,397.47 ± 1,777.22, 3,444.87 ± 2,145.82, and 1,283.81 ± 1,184.43 μm. The respective mean microdistortion lengths at each time-point were 1,781.29 ± 17,78.15, 2,617.78 ± 1,949.67, and 1,112.95 ± 1,245.88 μm in the thin lenticule group and 2,692.10 ± 1,825.20, 3,739.20 ± 2,072.60, and 1,332.44 ± 1,137.33 μm in the thick lenticule group. Microdistortions in Bowman's layer can remain 3 years after SMILE, but their lengths decrease over time. Thicker lenticules were associated with the early occurrence of microdistortions, but this effect decreased in the long term. [J Refract Surg. 2019;35(2):96-101.].