title: Changes in Keratocyte Density and Visual Function Five Years After Laser In Situ Keratomileusis: Femtosecond Laser Versus Mechanical Microkeratome.
abstract: OBJECTIVE
  To determine the effects of keratocyte loss on optical properties and vision after laser in situ keratomileusis (LASIK) with the flap created with a femtosecond laser or a mechanical microkeratome.
  
  
  METHODS
  Randomized clinical paired-eye study.
  
  
  METHODS
  Both eyes of 21 patients received LASIK for myopia or myopic astigmatism. One eye of each patient was randomized by ocular dominance to flap creation with a femtosecond laser and the other eye to flap creation with a mechanical microkeratome. Before LASIK and at 1, 3, and 6 months and 1, 3, and 5 years after LASIK, keratocyte density was measured using confocal microscopy, and high-contrast visual acuity and anterior corneal wavefront aberrations were measured by standard methods. At each visit, all variables were compared between methods of creating the flap and to the same variable before treatment using paired tests with Bonferroni correction for multiple comparisons.
  
  
  RESULTS
  Keratocyte density in the flap decreased by 20% during the first year after LASIK and remained low through 5 years (P < .001). High-order wavefront aberrations increased and uncorrected visual acuity improved immediately after surgery, but these variables did not change further to 5 years. There were no differences in any variables between treatments.
  
  
  CONCLUSIONS
  A sustained reduction in keratocyte density does not affect vision or optical properties of the cornea through 5 years after LASIK. The method of creating a LASIK flap does not influence the changes in keratocyte density in the flap.
authors: Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota.
authors: Jay W
authors: JW
authors: McLaren
authors: Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota.
authors: William M
authors: WM
authors: Bourne
authors: Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota.
authors: Leo J
authors: LJ
authors: Maguire
authors: Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota. Electronic address: patel.sanjay@mayo.edu.
authors: Sanjay V
authors: SV
authors: Patel
mesh_terms: D000328:Adult; D001251:Astigmatism / Q000503:physiopathology / Q000601:surgery; D002452:Cell Count; D060527:Corneal Keratocytes / Q000473:pathology*; D057108:Corneal Wavefront Aberration / Q000175:diagnosis; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D018613:Microscopy, Confocal; D008875:Middle Aged; D009216:Myopia / Q000503:physiopathology / Q000601:surgery*; D013524:Surgical Flaps / Q000473:pathology; D013997:Time Factors; D014792:Visual Acuity / Q000502:physiology*