title: Confocal microscopy of a patient with irregular astigmatism after LASIK reoperations and relaxation incisions.
abstract: OBJECTIVE
  Laser-assisted in situ keratomileusis (LASIK) is widely used for correcting refractive errors. If the predicted refractive result is not achieved after the first operation, a re-operation can be performed by ablating more stromal tissue after reopening the flap. The goal of this study was to analyze, by using in vivo confocal microscopy, the morphologic changes associated with repeated LASIKs.
  
  
  METHODS
  Clinical examination, computed corneal topography, and real-time in vivo confocal microscopy were performed on both eyes of a 50-year-old patient with induced irregular astigmatism leading to decreased best-corrected vision in the left eye after LASIK. The left cornea had been operated on 5 times (LASIK with two reoperations followed by two relaxing incisions), and the right cornea twice (LASIK with one reoperation).
  
  
  RESULTS
  Microfolds at the level of the Bowman's layer and highly reflective particles at the flap interface were observed in both corneas. The subbasal nerve plexus was severed in the left eye. In addition, we identified epithelial material in the flap margin and inside one of the two relaxing incisions placed inferotemporally.
  
  
  CONCLUSIONS
  Repeated LASIKs may stretch the flap and result in microfolding at the Bowman's layer. This and deposition of particles in the flap interface may increase with the number of reoperations, challenging the healing response. Microfolding and occurrence of foreign material in the interface may add to the irregular astigmatism and poor visual outcome after LASIK. Clinical in vivo confocal microscopy offers new possibilities for the assessment of ultrastructural changes after corneal refractive surgery.
authors.affiliation: Helsinki University Eye Hospital, Finland. tuuli.linna@huch.fi
authors.forename: T U
authors.initials: TU
authors.lastname: Linna
authors.forename: M H
authors.initials: MH
authors.lastname: Vesaluoma
authors.forename: W M
authors.initials: WM
authors.lastname: Petroll
authors.forename: A H
authors.initials: AH
authors.lastname: Tarkkanen
authors.forename: T M
authors.initials: TM
authors.lastname: Tervo
mesh_terms: D001251:Astigmatism / Q000209:etiology / Q000473:pathology*; D003315:Cornea / Q000473:pathology* / Q000601:surgery; D019781:Corneal Topography; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000009:adverse effects*; D008297:Male; D018613:Microscopy, Confocal; D008875:Middle Aged; D009216:Myopia / Q000601:surgery; D012086:Reoperation / Q000009:adverse effects; D012189:Retrospective Studies; D014792:Visual Acuity