title: Progressive keratectasia after laser in situ keratomileusis.
abstract: OBJECTIVE
  We describe ten patients who developed progressive keratectasia following laser in situ keratomileusis (LASIK) and identify possible factors that may lead to ectasia.
  
  
  METHODS
  In this retrospective study, we reviewed the files of 3,634 patients (6941 eyes) who had LASIK between March 2000 and April 2003. Ten patients (14 eyes, 0.2%) developed progressive keratectasia. We also evaluated consequent therapeutic measures and final visual status of these patients.
  
  
  RESULTS
  Patients were examined at a mean 24.9 +/- 8.1 months after LASIK. Ectasia developed within a mean 14 +/- 0.3 months after surgery. At baseline, mean keratometric power was 44.7 +/- 2.30 D, mean corneal thickness was 516 +/- 18.9 microm, and mean attempted correction was -10.85 +/- 3.20 D. We found a statistically significant correlation between residual stromal thickness, attempted correction, and occurrence of progressive keratectasia. We also found that preexisting abnormal corneal topography was a risk factor for progressive keratectasia. Ultimately, most patients had reasonable visual acuity after penetrating keratoplasty.
  
  
  CONCLUSIONS
  Progressive keratectasia is a vision threatening complication of LASIK that may occur in previously healthy or diseased eyes. The most important risk factors are residual stromal thickness and preexisting abnormal corneal topography. Penetrating keratoplasty may be a reasonable therapeutic measure for severe cases of progressive keratectasia.
authors.affiliation: Cornea and Refractive Section, Novin Didegan Eye Center, Tehran, Iran. a_s_rad@iranmedical.com
authors.forename: Ahmad Salamat
authors.initials: AS
authors.lastname: Rad
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Jabbarvand
authors.forename: Nader
authors.initials: N
authors.lastname: Saifi
mesh_terms: D000328:Adult; D003315:Cornea / Q000473:pathology*; D003316:Corneal Diseases / Q000209:etiology* / Q000503:physiopathology; D019781:Corneal Topography; D004108:Dilatation, Pathologic / Q000209:etiology; D018450:Disease Progression; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D014792:Visual Acuity