Visual Outcomes after Small Incision Lenticule Extraction and Femtosecond Laser-Assisted LASIK for High Myopia

<b><i>Purpose:</i></b> The aim of this study was to compare visual outcomes after small incision lenticule extraction (SMILE) and femtosecond laser-assisted in situ keratomileusis (FS-LASIK) for high myopia. <b><i>Methods:</i></b> In this prospective, comparative study, a total of 52 eyes of 34 consecutive highly myopic patients with spherical equivalent within the range of –8.00 to –10.00 diopters were recruited. Twenty-three eyes of 16 patients were in the FS-LASIK group and 29 eyes of 18 patients were in the SMILE group. Visual outcomes and wavefront aberrations were analyzed preoperatively and 6 months postoperatively. <b><i>Results:</i></b> At the postoperative 6-month visit, 96.6% in the SMILE group and 91.3% in the FS-LASIK group achieved unchanged or better corrected distance visual acuity (CDVA). As for uncorrected distance visual acuity (UDVA), 96.6% in the SMILE group and 95.7% in the FS-LASIK group achieved UDVA of 20/20 or better. As for wavefront aberrations, high-order aberrations (HOAs) and spherical aberrations increased significantly after surgery in both groups relative to corresponding preoperative values (<i>p</i> &#x3c; 0.001), and vertical coma increased after SMILE (<i>p</i> &#x3c; 0.001). No statistically significant differences in changes of HOAs (<i>p =</i>0.90), spherical aberrations (<i>p</i> = 0.07), horizontal coma (<i>p</i> = 0.56), coma (<i>p =</i>0.08), horizontal trefoil (<i>p =</i>0.19), vertical trefoil (<i>p</i> = 0.90), and trefoil (<i>p</i> = 0.45) were detected between the 2 groups, except for vertical coma (<i>p</i> &#x3c; 0.01). <b><i>Conclusions:</i></b> SMILE is as effective as FS-LASIK in correcting high myopia, but attention should be paid to the induction of vertical coma in highly myopic patients following a SMILE procedure.