title: Femtosecond laser versus mechanical microkeratome for LASIK: a randomized controlled study.
abstract: OBJECTIVE
  To compare corneal haze (backscattered light) and visual outcomes between fellow eyes randomized to LASIK with the flap created by a femtosecond laser (bladeless) or with the flap created by a mechanical microkeratome.
  
  
  METHODS
  Randomized, controlled, paired-eye study.
  
  
  METHODS
  Twenty-one patients (42 eyes) received LASIK for myopia or myopic astigmatism.
  
  
  METHODS
  One eye of each patient was randomized to flap creation with a femtosecond laser (IntraLase FS, IntraLase Corp., Irvine, CA) with intended thickness of 120 microm, and the fellow eye to flap creation with a mechanical microkeratome (Hansatome, Bausch & Lomb, Rochester, NY) with intended thickness of 180 microm. Patients were examined before and at 1, 3, and 6 months after LASIK.
  
  
  METHODS
  Corneal backscatter, high-contrast visual acuity, manifest refractive error, contrast sensitivity, and intraocular forward light scatter were measured at each examination. Flap thickness was measured by confocal microscopy at 1 month, and patients were asked if they preferred the vision in either eye at 3 months.
  
  
  RESULTS
  Corneal backscatter was 6% higher after bladeless LASIK than after LASIK with the mechanical microkeratome at 1 month (P = 0.007), but not at 3 or 6 months. High-contrast visual acuity, contrast sensitivity, and forward light scatter did not differ between treatments at any examination. Flap thicknesses at 1 month were 143+/-16 microm (bladeless, mean +/- standard deviation) and 138+/-22 microm (mechanical microkeratome), with no statistical difference in variances. At 3 months, 5 patients preferred the bladeless eye, 7 patients preferred the microkeratome eye, and 9 patients had no preference.
  
  
  CONCLUSIONS
  The method of flap creation did not affect visual outcomes during the first 6 months after LASIK. Although corneal backscatter was greater early after bladeless LASIK than LASIK with the mechanical microkeratome, patients did not perceive a difference in vision.
authors.affiliation: Department of Ophthalmology, Mayo Clinic College of Medicine, Rochester, Minnesota, USA. patel.sanjay@mayo.edu
authors.forename: Sanjay V
authors.initials: SV
authors.lastname: Patel
authors.forename: Leo J
authors.initials: LJ
authors.lastname: Maguire
authors.forename: Jay W
authors.initials: JW
authors.lastname: McLaren
authors.forename: David O
authors.initials: DO
authors.lastname: Hodge
authors.forename: William M
authors.initials: WM
authors.lastname: Bourne
mesh_terms: D000328:Adult; D001251:Astigmatism / Q000601:surgery*; D015350:Contrast Sensitivity / Q000502:physiology; D003319:Corneal Stroma / Q000601:surgery*; D023882:Dominance, Ocular; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000295:instrumentation / Q000379:methods*; D008027:Light; D018613:Microscopy, Confocal; D008875:Middle Aged; D009216:Myopia / Q000601:surgery*; D012542:Scattering, Radiation; D013524:Surgical Flaps; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology