Intraocular lens power calculation after corneal refractive surgery

Abstract

Challenges in IOL power calculation in eyes after corneal refractive surgery are caused by difficulties in accurately determining corneal refractive power and in predicting the effective lens position. Three factors contribute to inaccurate corneal refractive power estimation ‐ inaccurate measurement of anterior corneal curvature by standard keratometry or corneal topography, inaccurate calculation of total corneal power from the anterior corneal curvature can result from using the standardized value for the refractive index of cornea (1.3375) and finally changes in posterior corneal curvature. There are three categories of methods proposed based on the use of historical data acquired prior to the corneal refractive surgery (formulas using only historical data, no historical data or a combination of historical data and current data). The most frequently used methods of IOL power calculation in eyes after corneal refractive surgery are discussed and their accuracy are compared. The latest studies and meta‐analyses in this area are presented. Despite availability of new measurement technologies and development of new IOL calculation formulas, further advances are needed to improve outcomes of cataract surgery in eyes that have undergone corneal refractive surgery.