Influence of corneal astigmatism on near and far vision in eyes with bifocal intraocular lenses.

Abstract

Here, we present a full wave propagation model that quantitatively assesses the effect of astigmatism on visual functions in eyes with diffractive bifocal IOLs. The proposed model with bifocal IOLs evaluated the image quality of each focus at varying degrees of corneal astigmatism with the metrics of modulation transfer function and light-in-the-bucket. The results show that corneal astigmatism alters the distance-near image quality balance. Positive (negative) astigmatism has more detrimental effects on far (near) vision. Additionally, bifocal IOLs are more vulnerable to corneal astigmatism, highlighting the need to consider multifocal toric IOLs with astigmatism greater than 1.0 D. The numerical results closely agreed with previous relevant clinical findings, suggesting the clinical usability of the presented method in predicting the postoperative visual function of patients.