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

We report 2 cases of corneal ectasia detected after laser in situ keratomil eusis (LASIK) for the correction of less than -12.0 diopters (D) of myopia. Patients were evaluated before and after LASIK by corneal topography and p achymetry. After treatment, visual acuity temporarily improved but was foll owed by visual impairment, with corneal ectasia detected by topography. The re 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 restric ted to cases in which more than half the original corneal thickness and mor e than 250 mu m of the stromal bed can be preserved. Careful examination, i ncluding preoperative serial topographic evaluation and measurement of post erior stromal thickness, should be performed to improve the quality and pre dictability of corneal refractive surgery. (C) 2000 ASCRS and ESCRS.