Comparison of early visual outcomes following low-energy SMILE, high-energy SMILE, and LASIK for myopia and myopic astigmatism in the United States.

PURPOSE To compare uncorrected visual acuities (UDVA) and induced higher-order aberrations (HOAs) in the early postoperative period between low-energy (LE) small incision lenticule extraction (SMILE), high-energy (HE) SMILE and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) procedures. METHODS Records of patients who underwent SMILE or FS-LASIK were retrospectively reviewed. SMILE patients were separated into 2 groups: HE settings (125 nJ, 3.0 μm spot spacing) and LE settings (125 nJ-130 nJ, 4.5 μm spot spacing). UDVA was measured at postoperative day(POD) 1. Corneal HOAs and UDVA were measured at postoperative month (POM) 1. Induced spherical aberration, vertical coma, horizontal coma, total coma, and total HOAs were calculated. RESULTS The study included 147 eyes of 106 patients, 49 in each group. For SMILE patients, the difference in mean UDVA at POD 1 was highly statistically significant in favor of the LE group (-0.003 vs 0.141, p<0.0001). No significant difference in mean UDVA at POD 1 was noted between the LE group and FS-LASIK group (-0.003 vs -0.011, p= 0.498). Induced change in spherical aberration was less in LE SMILE than FS-LASIK (0.136 µm vs 0.186 µm, p=0.02) at POM 1. No significant differences in POM 1 mean UDVA (-0.033 vs -0.036) or induced change in all other HOAs were noted between LE SMILE and FS-LASIK. CONCLUSIONS LE settings were associated with significantly improved POD 1 UDVA. POD 1 and POM 1 UDVA were comparable to those of FS-LASIK. Spherical aberration induction was less with LE SMILE than FS-LASIK while all other induced HOAs were comparable to FS-LASIK.