2020–2021 BCSC Basic and Clinical Science Course™
3 Clinical Optics
Chapter 6: Intraocular Lenses
Intraocular Lens Power Calculation After Corneal Refractive Surgery
Special Consideration: Postoperative Refractive Surprise in Patients Who Have Undergone Myopic Keratorefractive Correction
Keratometers fail to measure the flattest portion of the cornea. This overestimation of corneal power will result in a hyperopic refractive surprise.
Keratometers and computerized corneal topographers underestimate the relative contribution of the posterior cornea and therefore overestimate the net corneal refractive index and overall corneal refractive power. This overestimation of corneal power will result in a hyperopic refractive surprise.
Standard IOL formulas estimate the ELP to be too anterior and therefore overestimate the refractive contribution of the IOL. This overestimation of IOL refractive contribution will result in a hyperopic refractive surprise.
Excerpted from BCSC 2020-2021 series : Section 3 - Clinical Optics. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.