title: Comparison of 2 femtosecond lasers for flap creation in myopic laser in situ keratomileusis: one-year results.
abstract: OBJECTIVE
  To compare laser in situ keratomileusis (LASIK) outcomes between 2 femtosecond lasers for flap creation in the treatment of myopia up to 1 year.
  
  
  METHODS
  University eye clinic.
  
  
  METHODS
  Prospective randomized eye-to-eye study.
  
  
  METHODS
  Consecutive myopic patients were treated with wavefront-guided LASIK. One eye had a flap created by the Intralase FS 60 kHz femtosecond laser, and the fellow eye was treated with the Intralase iFS 150 kHz femtosecond laser. Eyes were randomized according to ocular dominance. Evaluations included measurement of uncorrected distance visual acuity (UDVA), corrected distance visual acuity, contrast sensitivity and wavefront aberrometry.
  
  
  RESULTS
  The study enrolled 122 eyes of 61 patients. The mean preoperative spherical equivalent refraction was -4.62 diopters (D) ± 2.32 (SD) and -4.66 ± 2.30 D in the 150 kHz group and 60 kHz group, respectively. Patients preferred the 150 kHz laser to the 60 kHz laser intraoperatively (52.5% versus 26.2%) (P = .005). One week postoperatively, UDVA was 20/16 or better in 85.2% in the 150 kHz group and 70.5% in the 60 kHz group; the difference was statistically significant (P < .05). At 12 months, there were no significant differences in refractive outcomes or higher-order aberrations between the 2 groups.
  
  
  CONCLUSIONS
  Flap creation with the 150 kHz system and the 60 kHz system resulted in excellent LASIK outcomes. Intraoperatively, patients preferred the 150 kHz system, which yielded better UDVA in the early postoperative period. There were no significant differences at 1 year between the 2 laser systems.
  
  
  BACKGROUND
  Proprietary or commercial disclosures are listed after the references.
authors.affiliation: From the Byers Eye Institute at Stanford, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Charles Q
authors.initials: CQ
authors.lastname: Yu
authors.affiliation: From the Byers Eye Institute at Stanford, Stanford University School of Medicine, Stanford, California, USA. Electronic address: edward.manche@stanford.edu.
authors.forename: Edward E
authors.initials: EE
authors.lastname: Manche
mesh_terms: D057128:Aberrometry; D000328:Adult; D015350:Contrast Sensitivity / Q000502:physiology; D003319:Corneal Stroma / Q000601:surgery*; D057108:Corneal Wavefront Aberration / Q000503:physiopathology; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000295:instrumentation* / Q000379:methods; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000503:physiopathology / Q000601:surgery*; D011446:Prospective Studies; D013524:Surgical Flaps; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult