title: Comparison of ocular higher-order aberrations after SMILE and Wavefront-guided Femtosecond LASIK for myopia.
abstract: BACKGROUND
  To compare changes in higher-order aberrations (HOAs) following small incision lenticule extraction (SMILE) and wavefront-guided femtosecond laser-assisted in situ keratomileusis (WFG FS-LASIK), and to investigate correlations between preoperative spherical equivalence (SE) and components of HOAs affecting visual quality.
  
  
  METHODS
  Sixty-five myopic eyes from 38 patients were enrolled in the study retrospectively, either having undergone SMILE or WFG FS-LASIK. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refractive error, and individual Zernike coefficients of 3rd- to 6th-order HOAs were measured before and 3 months after the surgeries and were compared using the Mann-Whitney test or Student's t-test. Additional generalized estimating equation analyses (GEE) were used to control for within-subject biases in individual Zernike coefficients between the right and left eyes of the same patients.
  
  
  RESULTS
  There was no significant difference in UDVA or CDVA after WFG FS-LASIK (Mean ± SD: -0.02 ± 0.07 and -0.04 ± 0.22 respectively, in logMAR) and after SMILE (-0.01 ± 0.06 and -0.04 ± 0.04 respectively). However, greater vertical coma aberration was found after SMILE (p = 0.036). Preoperative SE was correlated to induced horizontal coma (r = -0.608, p = 0.001) in WFG FS-LASIK, and correlated to induced vertical coma (r = -0.459, p = 0.003) in SMILE.
  
  
  CONCLUSIONS
  Both SMILE and WFG FS-LASIK can achieve planned visual outcomes in correcting myopia and myopic astigmatism. However, higher vertical coma was shown in SMILE than WFG FS-LASIK which might be a potentially impact factor for patients' vision under certain lighting conditions and needs further investigation.
authors.affiliation: Tianjin Eye Hospital & Eye Institute, Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Medical University, No 4. Gansu Rd, Heping District, Tianjin, 300020, China.
authors.forename: Xiaoqin
authors.initials: X
authors.lastname: Chen
authors.affiliation: Tianjin Eye Hospital & Eye Institute, Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Medical University, No 4. Gansu Rd, Heping District, Tianjin, 300020, China. wangyan7143@vip.sina.com.
authors.forename: Yan
authors.identifier: http://orcid.org/0000-0002-1257-6635
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Tianjin Eye Hospital & Eye Institute, Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Medical University, No 4. Gansu Rd, Heping District, Tianjin, 300020, China.
authors.forename: Jiamei
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Vision Performance Institute, Pacific University College of Optometry, Forest Grove, OR, USA.
authors.forename: Shun-Nan
authors.initials: SN
authors.lastname: Yang
authors.affiliation: First Hospital of Qinhuangdao, Qinhuangdao, Hebei, China.
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Li
authors.affiliation: Tianjin Eye Hospital & Eye Institute, Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Medical University, No 4. Gansu Rd, Heping District, Tianjin, 300020, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Zhang
mesh_terms: D057128:Aberrometry; D000328:Adult; D057108:Corneal Wavefront Aberration / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000379:methods*; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D009216:Myopia / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D011183:Postoperative Complications; D012029:Refraction, Ocular; D012189:Retrospective Studies; D014792:Visual Acuity; D055815:Young Adult
keywords: Refractive surgery; Small incision lenticule extraction; Visual quality; Wavefront aberration; Wavefront-guided femtosecond LASIK