title: Comparison of laser in situ keratomileusis flaps created by 2 femtosecond lasers.
abstract: OBJECTIVE
  To compare flap morphology created by the WaveLight FS200 femtosecond laser and the VisuMax femtosecond laser, assessing the uniformity, accuracy, and predictability of flap creation.
  
  
  METHODS
  A total of 400 eyes had corneal flaps created with the WaveLight FS200 femtosecond laser (200 eyes) or the VisuMax femtosecond laser (200 eyes). The desired flap thickness was 110 μm. At 1 week postoperatively, all eyes were evaluated with RTVue Fourier-domain optical coherence tomography. Dimensions of the flaps were tested for their regularity, uniformity, accuracy, and predictability comparison.
  
  
  RESULTS
  One week after surgery, the central flap thickness and the mean flap thickness of the FS200 group were 105.4 ± 3.4 μm and 105.7 ± 2.6 μm, respectively. They were both thinner than those of the VisuMax group, which were 110.8 ± 3.9 μm and 111.3 ± 2.3 μm, respectively. The mean deviation between the achieved and attempted flap thickness of the FS200 group (5.2 ± 1.9 μm) was greater than that of the VisuMax group (3.2 ± 1.8 μm). Flap thickness measurements at 36 points in both groups were close to the intended thickness. Morphology of the flaps in the 0-, 45-, 90-, and 135-degree lines created by the FS200 femtosecond laser and VisuMax femtosecond laser were uniform and regular.
  
  
  CONCLUSIONS
  Flap dimensions created by the WaveLight FS200 femtosecond laser and VisuMax femtosecond laser were uniform and regular. Although the flap thickness created by the FS200 was less than that created by the VisuMax, measurements of both femtosecond lasers were close to the intended thickness.
authors.affiliation: Ophthalmic Center, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology and Visual Sciences Key Lab, Beijing, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zheng
authors.forename: Yuehua
authors.initials: Y
authors.lastname: Zhou
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.forename: Qian
authors.initials: Q
authors.lastname: Liu
authors.forename: Changbin
authors.initials: C
authors.lastname: Zhai
authors.forename: Yonghua
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000328:Adult; D003319:Corneal Stroma / Q000473:pathology / Q000601:surgery*; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000379:methods*; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D009216:Myopia / Q000601:surgery*; D011446:Prospective Studies; D013524:Surgical Flaps / Q000473:pathology*; D041623:Tomography, Optical Coherence; D014792:Visual Acuity; D055815:Young Adult