Comparative numerical analysis of astigmatism tolerance in bifocal, extended depth-of-focus, and trifocal intraocular lenses

Jongin You, Mooseok Jang

Here, we quantitatively assess the effect of astigmatism on visual functions in eyes with three different commercial multifocal intraocular lenses (IOLs) using a customized finite eye model. Our proposed model implements a full wave analysis of the whole eye structure with diffractive multifocal IOLs under polychromatic conditions. The proposed eye model evaluates the energy efficiency of each focus at varying degrees of corneal astigmatism with the light-in-the-bucket metrics for bifocal (Restor), extended depth-of-focus (Symfony), and trifocal IOLs (POD-F). Better tolerance under astigmatic conditions was observed in the order of Symfony, Restor, and POD-F, highlighting the need to consider multifocal toric IOLs with corneal astigmatism greater than +1.5 D, + 1.0 D, and +1.0 D for Symfony, Restor, and POD-F, respectively. Furthermore, we revealed the way that the optical properties of multifocal IOLs, including the optical power of the diffractive part, the effect of high-order harmonics, and chromatic aberration, interplay to determine the tolerance for corneal aberration. The numerical analysis closely agrees with previous clinical studies on determining the indication for multifocal toric IOLs, suggesting the clinical usability of the presented method in predicting the postoperative visual function of patients on a customized basis.