The Effect of Preoperative Corneal Asphericity on the Refractive Outcomes of Multifocal Intraocular Lens Implantation

Abstract

Purpose: To analyze the effects of preoperative corneal asphericity on the refractive outcomes of multifocal intraocular lens implantation by correlating Q-values on anterior corneal surfaces and the prediction errors after surgery. Methods: Fifty-six eyes of 39 patients who underwent phacoemulsification, and multifocal intraocular lens implantation were included in this retrospective study. Intraocular lens power was calculated using the SRK/T, Hoffer Q, and Haigis formulas. The Q-values were measured at 6 mm, 7 mm, 8 mm, 9 mm, and 10 mm with a rotating Sheimpflug camera (Pentacam ® , Oculus, Wetzlar, Germany). The relationship between the prediction errors and the Q-values at 6 mm, 7 mm, 8 mm, 9 mm, and 10 mm were assessed by linear regression. Results: Two different multifocal intraocular lens models (Acrysof IQ RESTOR +2.5D SV25T0 [Alcon Laboratories Inc., Fort Worth, TX, USA] and ZEISS AT LISA tri 839MP [Carl Zeiss Meditec AG, Inc., Jena, Germany]) were implanted in 56 eyes. In both groups, regression analyses showed statistically significant relationships between the prediction errors and the Q-values at 6 mm, 7 mm, and 8 mm using the SRK/T formula. The correlation coefficient between the Q-values and the prediction errors were higher using the SRK/T formula than using the Hoffer-Q and Haigis formulas. Conclusions: Corneal asphericity affected refractive power during implantation of a multifocal intraocular lens and, as the preoperative Q-value increased, it resulted in a hyperopic refractive outcome for oblate corneas. These results were especially prominent when the SRK/T formula was used.