#### Abstract

By Thomas Olsen, MD, PhD The calculation of IOL power in an eye that has undergone corneal refractive surgery is not a straightforward task. However, if you understand why the calculation may go wrong, you will have a fair chance of getting a good result using modern technology. It is important to understand that the calculation errors of post-LASIK eyes are the sum of the traditional errors plus the errors associated with the abnormal corneal shape. The post-LASIK eye exposes some of the weaknesses of the traditional IOL power calculation formulas.