A patient was treated bilaterally for myopia using laser in situ keratomileusis (LASIK). Preoperatively, there was no known risk factor for ectasia but a 20 microm between-eye difference in central mean corneal thickness was seen on the optical pachymetry map. Two years postoperatively, bilateral ectasia was diagnosed. This case suggests that abstention or surface ablation treatment may be a safer option than LASIK in patients showing central thickness asymmetry between eyes.