title: Laser in situ keratomileusis: ablation on the flap and stromal bed in a primary treatment.
abstract: OBJECTIVE
  To analyze outcomes of laser in situ keratomileusis (LASIK) performed on the flap and on the stromal bed at the same time in a primary treatment.
  
  
  METHODS
  Instituto de la Visión, Buenos Aires, Argentina.
  
  
  METHODS
  Twenty-two cases (13 female, 9 male) were studied retrospectively; the mean age of the patients was 33.15 years +/- 10.44 (SD). Inclusion criteria were low pachymetry or topographic asymmetry. Twenty cases (90.9%) presented with low pachymetry (512.2 +/- 21.40 mum), and 2 cases (9.1%) presented with topographic asymmetry (inferior-superior difference more than 1.5 diopters [D]). Ablation was performed on the flap from the back and on the bed. The flap was made using the Technolas Hansatome microkeratome and the ablation by the Technolas 217z excimer laser (both by Bausch & Lomb). Preoperatively, the spherical equivalent (SE) was -5.61 +/- 1.72 D, the cylinder was -1.78 +/- 1.24 D, and the best spectacle-corrected visual acuity (BSCVA) was 0.77 +/- 0.19. Difficulties and complications of the technique, efficacy and safety index, and aberrations were analyzed.
  
  
  RESULTS
  According to the surgical plan and our nomogram, diopters corrected on the flap were -1.73 +/- 1.08 and on the bed were -4.77 +/- 1.89. The mean follow-up was 8.28 +/- 2.19 months. At 6 months, the SE was -0.21 +/- 0.39, vectorial change was 1.69 +/- 0.74, and the BSCVA was 0.77 +/- 0.20. Postoperatively, no eye had an increase in refractive astigmatism. Uncorrected visual acuity was 20/40 or better in all cases (100%) and 20/25 or better in 13 cases (59.1%). Regarding gained and lost lines of BSCVA, 54.5% conserved the lines, 18.2% lost 1 line, 9.1% gained 1 line, and 18.2% gained 2 lines.
  
  
  CONCLUSIONS
  Simultaneous ablation on the flap and on the bed in cases of low pachymetry or topographical asymmetry was predictable, effective, and safe.
authors.affiliation: Instituto de la Visión, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.
authors.forename: Carlos
authors.initials: C
authors.lastname: Argento
authors.forename: María José
authors.initials: MJ
authors.lastname: Cosentino
mesh_terms: D000328:Adult; D003319:Corneal Stroma / Q000000981:diagnostic imaging / Q000601:surgery*; D019781:Corneal Topography; D004108:Dilatation, Pathologic / Q000517:prevention & control; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000379:methods*; D008297:Male; D009216:Myopia / Q000601:surgery*; D049451:Nomograms; D011183:Postoperative Complications / Q000517:prevention & control; D012189:Retrospective Studies; D013524:Surgical Flaps; D016896:Treatment Outcome; D014463:Ultrasonography; D014792:Visual Acuity / Q000502:physiology