title: Flap thickness in eyes with ectasia after laser in situ keratomileusis.
abstract: OBJECTIVE
  To measure central flap thickness in eyes with ectasia after laser in situ keratomileusis (LASIK) and to compare these values with estimated anticipated flap thickness based on mean published values for each device used for flap creation.
  
  
  METHODS
  Emory Vision at Emory University, Atlanta, Georgia, USA.
  
  
  METHODS
  Retrospective comparative case series, using published data for controls.
  
  
  METHODS
  Confocal microscopic analysis was performed using the Confoscan 3 device to measure central flap thickness in eyes with ectasia after LASIK. Pre-LASIK records were evaluated for information, including basic patient demographics, preoperative corneal topographies, estimated anticipated flap thickness based on the mean average thickness values, and residual stromal bed (RSB) thickness calculations using measured and estimated flap thicknesses.
  
  
  RESULTS
  Fifty eyes of 29 patients were evaluated. The mean measured flap thickness was 138 μm ± 26 (SD) (range 90 to 220 μm). There were no significant differences between measured and estimated flap thicknesses (138 μm versus 135 μm; P=.5) or RSB thickness (329 μm versus 332 μm; P=.7), nor were there differences in flap thickness between eyes developing ectasia with normal corneal topographies and eyes with abnormal corneal topographies. One eye had a measured flap resulting in an unintended RSB thickness less than 250 μm; this eye also had abnormal topography.
  
  
  CONCLUSIONS
  Measured central flap thickness was not thicker than estimated in most eyes developing ectasia after LASIK. Thus, excessively thick flaps do not appear to be a major contributing factor to the pathogenesis of ectasia after LASIK.
  
  
  BACKGROUND
  No author has a financial or proprietary interest in any material or method mentioned.
authors.affiliation: Emory Vision at the Emory Eye Center, Atlanta, Georgia 30322, USA. jrandle@emory.edu
authors.forename: J Bradley
authors.initials: JB
authors.lastname: Randleman
authors.forename: Carolyn B
authors.initials: CB
authors.lastname: Hebson
authors.forename: Paul M
authors.initials: PM
authors.lastname: Larson
mesh_terms: D000328:Adult; D003316:Corneal Diseases / Q000209:etiology / Q000473:pathology*; D003319:Corneal Stroma / Q000473:pathology*; D019781:Corneal Topography; D004108:Dilatation, Pathologic / Q000209:etiology / Q000473:pathology; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D018613:Microscopy, Confocal; D008875:Middle Aged; D011183:Postoperative Complications; D012189:Retrospective Studies; D013524:Surgical Flaps / Q000473:pathology*; D055815:Young Adult