title: Longitudinal comparison of outcomes after sub-Bowman keratomileusis and laser in situ keratomileusis: randomized, double-masked study.
abstract: OBJECTIVE
  To compare the outcomes of sub-Bowman keratomileusis (100-μm flap) and laser in situ keratomileusis (LASIK) (120-μm flap) using 150-kHz femtosecond laser.
  
  
  METHODS
  Randomized, double-masked, contralateral clinical trial.
  
  
  METHODS
  One hundred patients (200 eyes) with myopia or myopic astigmatism were included. Postoperative examinations were performed at week 1 and months 1, 3, 6, and 12. Main outcome measures included postoperative uncorrected (UCVA) and best-corrected distance visual acuity (BCVA); manifest refraction spherical equivalent; efficacy and safety indices; corneal thickness; and complications.
  
  
  RESULTS
  The mean age of patients was 33.9 ± 7.9 years. Overall, the preoperative UCVA, BCVA, and manifest refraction spherical equivalent were 1.349 ± 0.332, -0.022 ± 0.033, and -5.81 ± 1.61 diopters, respectively. No significant difference was observed in preoperative (P ≥ .226) or intraoperative parameters (P ≥ .452) between both groups, except residual stromal thickness (P < .001). The UCVA, manifest refraction spherical equivalent, and central corneal thickness stabilized by 1 week, while the thinnest corneal thickness stabilized by 3 months postoperatively. There was no significant difference between both groups for any parameter during all follow-up visits (P ≥ .132) except the 3-month safety index, which was better in the sub-Bowman keratomileusis group (P = .007). Soft opaque bubble layer was noted intraoperatively in 12 cases (7, 100-μm group; 5, 120-μm group; P = .577). No postoperative complications were observed.
  
  
  CONCLUSIONS
  Our study did not find any differences in the visual and refractive outcomes between femtosecond-assisted sub-Bowman keratomileusis and LASIK. Both surgeries resulted in quick visual recovery as early as 1 week postoperatively.
authors: Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China.
authors: Rachel Chung Yin
authors: RC
authors: Wong
authors: Department of Mathematics and Statistics, Hang Seng Management College, Hong Kong, China.
authors: Marco
authors: M
authors: Yu
authors: Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China; Hong Kong Eye Hospital, Hong Kong, China.
authors: Tommy C Y
authors: TC
authors: Chan
authors: Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China.
authors: Kelvin K L
authors: KK
authors: Chong
authors: Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China; Hong Kong Eye Hospital, Hong Kong, China. Electronic address: vishaljhanji@gmail.com.
authors: Vishal
authors: V
authors: Jhanji
mesh_terms: D000328:Adult; D001251:Astigmatism / Q000503:physiopathology / Q000601:surgery*; D050541:Bowman Membrane / Q000601:surgery*; D063171:Corneal Pachymetry; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000379:methods*; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000503:physiopathology / Q000601:surgery*; D012029:Refraction, Ocular / Q000502:physiology; D013524:Surgical Flaps; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult