Corneal ectasia detected after laser in situ keratomileusis for correction of less than-12 diopters of myopia

We report 2 cases of corneal ectasia detected after laser in situ keratomileusis (LASIK) for the correction of less than -12.0 diopters (D) of myopia. Patients were evaluated before and after LASIK by corneal topography and pachymetry. After treatment, visual acuity temporarily improved but was followed by visual impairment, with corneal ectasia detected by topography. There may be a risk of corneal ectasia after LASIK in cases of myopia of less than -12.0 D. Despite the low incidence, we recommend that LASIK be restricted to cases in which more than half the original corneal thickness and more than 250 mu m of the stromal bed can be preserved. Careful examination, including preoperative serial topographic evaluation and measurement of posterior stromal thickness, should be performed to improve the quality and predictability of corneal refractive surgery. (C) 2000 ASCRS and ESCRS.