Atlanta-When performing aphakic IOL calculations in eyes that have undergone corneal refractive surgery, contact lens over-refraction is the single best method for determining the value of corneal power (K). When preoperative K is known, averaging values obtained from both contact lens over-refraction and the keratometric history technique yields even better results. Nevertheless, both techniques remain suboptimal, yielding highly variable results, according to George O. Waring III, MD.
