Comparison of the optical quality after SMILE and FS-LASIK for high myopia by OQAS and iTrace analyzer: a one-year retrospective study

BACKGROUND: To compare the correction effect and optical quality after small-incision lenticule extraction (SMILE) and femtosecond laser assisted laser in situ keratomileusis (FS-LASIK) for high myopia. METHODS: 51 high myopia eyes after SMILE and 49 high myopia eyes after FS-LASIK were enrolled and divided into two groups retrospectively. The OQAS and iTrace analyzer were used for optical quality inspection. Between the two groups the spherical equivalent (SE), astigmatism, uncorrected distant visual acuity (UDVA), strehl ratio (SR), modulation transfer function cutoff frequency (MTF cutoff), objective scatter index (OSI) and wavefront aberrations were analyzed and compared before surgery and at 1, 6 and 12 months after surgery. RESULTS: After the operation: (1) SE and astigmatism declined and UDVA increased significantly in both groups, and UDVA was better after SMILE than FS-LASIK. (2) SR and MTF cutoff reduced and OSI increased significantly after SMILE and FS-LASIK. SR and MTF cutoff were significantly higher after SMILE than FS-LASIK. OSI was significantly lower after SMILE than FS-LASIK. (3) The total wavefront aberration, total low-order wavefront aberration, defocus and astigmatism aberration as well as trefoil aberration reduced significantly in both groups. The total high-order wavefront aberration increased significantly after FS-LASIK. The spherical and coma aberration increased significantly in both groups. The total high-order wavefront aberration and coma aberration at 1 month were higher after FS-LASIK than SMILE. CONCLUSION: The optical quality descended after SMILE and FS-LASIK. SMILE was superior to FS-LASIK at the correction effect and optical quality for high myopia. The combination of OQAS and iTrace analyzer is a valuable complementary measurement in evaluating the optical quality after the refractive surgery. TRIAL REGISTRATION: This is a retrospective study. This research was approved by the ethics committee of Xiangya Hospital and the IRB approval number is 201612074.