title: Comparison of the corneal response to laser in situ keratomileusis with flap creation using the FS15 and FS30 femtosecond lasers: clinical and confocal microscopy findings.
abstract: OBJECTIVE
  To compare the response of the cornea to laser in situ keratomileusis (LASIK) with flap creation using the IntraLase FS15 or FS30 femtosecond laser (IntraLase Corp.).
  
  
  METHODS
  Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
  
  
  METHODS
  Twenty-three patients (31 eyes) who had LASIK with flap creation using the FS15 or FS30 laser were assessed by clinical examination and confocal microscopy in a nonrandomized parallel treatment group comparative trial. Eight FS15 patients (15 eyes) were examined preoperatively and 3 months postoperatively, and 14 FS30 patients (15 eyes) were examined 3 months postoperatively.
  
  
  RESULTS
  No patient in either group had clinically significant flap interface haze. One FS15 eye and 1 FS30 eye had significant keratocyte activation at the flap interface. The mean difference between the actual flap thickness and intended flap thickness was 16.8 microm +/- 11.1 (SD) and 13.9 +/- 7.1 microm in the FS15 group and FS30 group, respectively (P = .49). The mean measured interface reflectivity was 156.4 +/- 88.6 confocal backscatter units (CBU) and 104.8 +/- 91.2 CBU, respectively (P = .15). The mean density of interface particles was 21.4 +/- 14.8 particles/mm(2) in the FS15 group and 11.0 +/- 7.1 particles/mm(2) in the FS30 group (P<.05).
  
  
  CONCLUSIONS
  Both the FS15 and FS30 lasers provided more reproducible flap thickness and fewer interface particles than previously observed using microkeratomes. The response of corneal keratocytes to intra-LASIK was reduced compared with previous results in which higher raster energies were used. Compared with the FS15, there was an apparent reduction in overall interface reflectivity and fewer interface particles with the FS30 laser.
authors.affiliation: University of Texas Southwestern Medical School, USA.
authors.forename: Michael Y
authors.initials: MY
authors.lastname: Hu
authors.forename: James P
authors.initials: JP
authors.lastname: McCulley
authors.forename: H Dwight
authors.initials: HD
authors.lastname: Cavanagh
authors.forename: R Wayne
authors.initials: RW
authors.lastname: Bowman
authors.forename: Steven M
authors.initials: SM
authors.lastname: Verity
authors.forename: V Vinod
authors.initials: VV
authors.lastname: Mootha
authors.forename: W Matthew
authors.initials: WM
authors.lastname: Petroll
mesh_terms: D003319:Corneal Stroma / Q000473:pathology* / Q000601:surgery; D005347:Fibroblasts / Q000473:pathology; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000295:instrumentation / Q000379:methods*; D007834:Lasers; D018613:Microscopy, Confocal; D009216:Myopia / Q000601:surgery*; D013524:Surgical Flaps / Q000473:pathology*; D014792:Visual Acuity; D014945:Wound Healing