RESUMEN
To report late onset corneal ectasia following myopic LASIK. Methods: A retrospective cohort case series. Nineteen patients with late onset corneal ectasia following LASIK procedure were examined at The Eye Center, Riyadh, Saudi Arabia. Patients underwent LASIK for myopia with spherical equivalent ranging from -1.4 to -13.75 diopters. Age and gender, history of systemic or local diseases, and time of onset of corneal ectasia were recorded. Eye examination and corneal topographical analyses were done before and after LASIK surgery. Results: Nineteen patients [29 eyes] with late onset corneal ectasia were identified from 1998 to 2008 in 13 male and six female patients. The mean follow-up period was 108 +/- 23 months [range 72-144 months]. No patient had pre-operative identifiable risk factors for corneal ectasia and the mean time of onset was 57 +/- 24 months [range 24-120 months after LASIK]. The pre-operative values included mean central pachymetry 553 +/- 25 urn, mean keratometry reading of 42.9 +/- 1.5 diopters, average oblique cylinder of 1.4 +/- 1.2 diopters, posterior surface elevation of 26 +/- 2.1 diopters, corneal flap thickness of 160 urn, mean spherical equivalent of -5.6 +/- 3.6 diopters, and calculated residual corneal stromal bed thickness was 288 +/- 35 um. Three [5 eyes] patients developed ectasia after pregnancy. Three [4 eyes] patients developed corneal ectasia following severe adenoviral keratoconjunctivitis and had positive PCR for adenovirus type 8. Conclusions: Corneal ectasia may develop many years after LASIK surgery and symptoms could go undetected for some time. Pregnancy and adenoviral keratoconjunctivitis occurred post-opera-tively in six patients