Corneal ectasia induced by laser in situ keratomileusis.

PURPOSE To identify factors that can lead to corneal ectasia after laser in situ keratomileusis (LASIK). SETTING University refractive surgery center. METHODS In this retrospective study, the charts of all patients (2873 eyes) who had LASIK between May 1995 and November 1999 were reviewed. Fourteen patients (19 eyes, 0.66%) developed post-LASIK ectasia. The mean follow-up was 16.32 months (range 6 to 42 months). RESULTS No patient with an attempted correction less than 8.00 diopters or a residual corneal bed thickness greater than 325 microm experienced post-LASIK ectasia. There was a statistically significant positive correlation between corneal residual bed thickness and increasing patient age. CONCLUSION Despite the limitations of the small sample size, the study's results suggest that parameters besides residual corneal bed thickness (eg, age, attempted correction) may have to be considered to avoid post-LASIK ectasia.