title: Pathogenesis and management of laser in situ keratomileusis flap buttonhole.
abstract: OBJECTIVE
  To describe the clinical features and outcomes in patients who had a flap buttonhole during laser in situ keratomileusis (LASIK) and propose an etiopathogenic mechanism for this complication.
  
  
  METHODS
  University Eye Center, Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China.
  
  
  METHODS
  Retrospective review of case records of 6 patients (6 eyes) who had a flap buttonhole during LASIK.
  
  
  RESULTS
  The mean patient age was 38.2 years +/- 4.1 (SD) and the mean preoperative spherical equivalent (SE) refraction, -8.13 +/- 4.04 diopters (D). Mean keratometry was 44.20 +/- 1.30 D. Retreatment was performed after a mean interval of 9.2 +/- 3.2 months. Final postoperative SE refraction was -0.44 +/- 0.58 D after a mean follow-up of 59.0 +/- 5.3 weeks. No patient experienced loss of best spectacle-corrected visual acuity.
  
  
  CONCLUSIONS
  Retreatment of eyes that have a flap buttonhole during LASIK is associated with good visual outcomes. Flap buttonholes can produce alterations in refraction, so retreatment is best performed after the refractive error has stabilized. Microkeratome malfunction may be responsible for the occurrence of a flap buttonhole during LASIK in eyes that do not have significant corneal steepening.
authors.affiliation: Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong, People's Republic of China.
authors.forename: A T
authors.initials: AT
authors.lastname: Leung
authors.forename: S K
authors.initials: SK
authors.lastname: Rao
authors.forename: A C
authors.initials: AC
authors.lastname: Cheng
authors.forename: E W
authors.initials: EW
authors.lastname: Yu
authors.forename: D S
authors.initials: DS
authors.lastname: Fan
authors.forename: D S
authors.initials: DS
authors.lastname: Lam
mesh_terms: D000328:Adult; D003316:Corneal Diseases / Q000209:etiology* / Q000473:pathology / Q000601:surgery; D005260:Female; D006801:Humans; D007431:Intraoperative Complications; D020731:Keratomileusis, Laser In Situ / Q000009:adverse effects*; D008297:Male; D009216:Myopia / Q000601:surgery; D012029:Refraction, Ocular; D012086:Reoperation; D012189:Retrospective Studies; D012422:Rupture, Spontaneous; D013524:Surgical Flaps / Q000473:pathology*; D016896:Treatment Outcome; D014792:Visual Acuity