Abstract
Purpose :
To compare the optical and predicted clinical performance of a higher-order aspheric IOL design that provides a continuous change in power from the center to the periphery of the lens with a zonal refractive IOL with a distinct add power of 2D in the central zone using optical bench measurements and simulations.
Methods :
Binocular visual acuity (sVA) was simulated using the metrics described in Alarcon et al. BOE 2016, calculated from measurements collected in an average corneal eye (ACE) model, in white light, with 3mm pupil and from -2.5D to 0.5D of defocus. Distance image quality was evaluated by the modulation transfer function (MTF) measured in the ACE model, in white light, for 2, 3 and 5mm pupils. Computer simulations in a physiological eye were performed to determine the halo profile for different pupil sizes for the different IOL designs. Measurements of a standard monofocal and a diffractive multifocal IOL of 2.75D add power were included as references.
Results :
The higher-order aspheric IOL provides comparable distance sVA to the monofocal IOL and an extended depth of focus in the intermediate range with a monotonical decrease in through-focus sVA. The zonal refractive design provided a decrease of 1 line of sVA at distance and a bifocal defocus curve with a second peak that corresponds to the add power. The design with the central add power showed a lower contrast for all pupil sizes than the higher order aspheric IOL and at the level of the multifocal IOL for 3 and 5mm. For 2mm, the central add power design provided a reduction in contrast with MTF close to zero. Contrary, the higher order aspheric design resulted in consistent distance image quality through different pupil sizes. The pupil dependency of the zonal refractive design was also visible in the halo pictures simulations, with perception of halos and rings especially for the smaller pupils, which are not visible in the higher-order aspheric IOL for any of the pupil sizes evaluated.
Conclusions :
The addition of an add power results in a strong pupil dependence and an optical performance that resembles a standard multifocal IOL, with a bifocal defocus curves, a loss in distance image quality and the perception of halos. The higher-order aspheric IOL, that creates a continuous change in power to extend the depth of focus and improve intermediate vision, provides a pupil independent performance and a consistent dysphotopsia profile.
This is a 2021 ARVO Annual Meeting abstract.