title: Rate of ectasia and incidence of irregular topography in patients with unidentified preoperative risk factors undergoing femtosecond laser-assisted LASIK.
abstract: OBJECTIVE
  To report the rate of postoperative ectasia after laser-assisted in situ keratomileusis (LASIK) with femtosecond laser-assisted flap creation, in a population of patients with no identified preoperative risk factors.
  
  
  METHODS
  A retrospective case review of 1,992 eyes (1,364 patients) treated between March 2007 and January 2009 was conducted, with a follow up of over 4 years. After identifying cases of ectasia, all the patient charts were examined retrospectively for preoperative findings suggestive of forme fruste keratoconus (FFKC).
  
  
  RESULTS
  Five eyes of four patients with post-LASIK ectasia were identified. All eyes passed preoperative screening and received bilateral LASIK. One of the five patients developed ectasia in both eyes. Three patients retrospectively revealed preoperative topography suggestive of FFKC, while one patient had no identifiable preoperative risk factors. Upon review of all the charts, a total 69 eyes, including four of the five eyes with ectasia, were retrospectively found to have topographies suggestive of FFKC.
  
  
  CONCLUSIONS
  We identified four cases of post-LASIK ectasia that had risk factors for FFKC on reexamination of the chart and one case of post-LASIK ectasia with no identifiable preoperative risk factors. The most conservative screening recommendations would not have precluded this patient from LASIK. The rate of purely iatrogenic post-LASIK ectasia at our center was 0.05% (1/1,992), and the total rate of post-LASIK ectasia for our entire study was 0.25% (1/398). The rate of eyes with unrecognized preoperative FFKC that developed post-LASIK ectasia was 5.8% (1/17).
authors.affiliation: John A Moran Eye Center, University of Utah, Salt Lake City, UT, USA.
authors.forename: Majid
authors.initials: M
authors.lastname: Moshirfar
authors.affiliation: College of Human Medicine, Michigan State University, Lansing, MI, USA.
authors.forename: Jared G
authors.initials: JG
authors.lastname: Smedley
authors.affiliation: John A Moran Eye Center, University of Utah, Salt Lake City, UT, USA.
authors.forename: Valliammai
authors.initials: V
authors.lastname: Muthappan
authors.affiliation: Department of Ophthalmology, State University of New York Upstate Medical University, Syracuse, NY, USA.
authors.forename: Allison
authors.initials: A
authors.lastname: Jarsted
authors.affiliation: John A Moran Eye Center, University of Utah, Salt Lake City, UT, USA.
authors.forename: Erik M
authors.initials: EM
authors.lastname: Ostler
keywords: LASIK; ectasia; forme fruste keratoconus; topography; visual acuity