Adaptive-Optics-Based Simulation of Astigmatism Effects on Visual Acuity with Enhanced Monofocal Intraocular Lenses

To investigate the effect of low-to-moderate astigmatism magnitude, axis orientation and pupil size on distance and intermediate visual acuity with two enhanced monofocal intraocular lenses (IOL) using adaptive optics simulation.

This prospective, observational, within-subject comparative study included 24 presbyopic participants aged 50-69 years. Two enhanced monofocal IOLs (RayOne EMV and Tecnis Eyhance) were simulated using the SimVis Gekko adaptive optics visual simulator over the manifest distance refraction. Corrected-distance visual acuity (CDVA, 4 m) and distance-corrected intermediate visual acuity (DCIVA, 60 cm) were measured at baseline and with induced simple hyperopic astigmatism (+0.50, +1.00 and +1.50 D) at against-the-rule (ATR) and with-the-rule (WTR). Simulated pupil diameter was 3.0 mm for distance and 3.0 and 4.0 mm for intermediate vision. Visual acuity degradation relative to baseline (ΔVA) was analysed separately for both distances using linear mixed-effects models including IOL, astigmatism magnitude, axis orientation and pupil diameter as fixed effects. Significant IOL effects were explored using Holm-adjusted pairwise comparisons.

At a far distance, baseline CDVA was similar between IOLs (p = 0.79) and ΔVA increased significantly with astigmatic magnitude (p < 0.001), being greater for WTR than ATR astigmatism (p < 0.001), with no significant IOL effect. Baseline DCIVA differed between IOLs and pupil size (both p < 0.001), with Eyhance showing better VA with a 3.0 mm pupil (p < 0.001). ΔVA increased with astigmatism magnitude (p < 0.001), axis orientation (p < 0.001) and pupil diameter (p < 0.001), with no significant differences between IOLs (p = 0.50).

With simulated enhanced monofocal IOLs, VA deteriorates progressively with increasing hyperopic astigmatism at both distance and intermediate vision, with cylinder magnitude as the main determinant. Axis orientation and pupil diameter further modulate intermediate visual performance, while astigmatic tolerance remains comparable between RayOne EMV and Tecnis Eyhance across all tested conditions.