Physiological chromatic model eyes for IOL characterization

Accurate optical bench characterization of intraocular lenses (IOLs) under white-light conditions requires model eyes that reproduce both physiological spherical aberration (SA) and longitudinal chromatic aberration (LCA). Although current ISO and ANSI standards adopt a physiological reference for LCA under polychromatic testing, a rigorous framework is still needed to determine whether a complete bench system reproduces a physiologically meaningful chromatic baseline. To address this issue, we propose a chromatic model eye based on an achromatic doublet cornea compatible with standard ISO and ANSI geometries. Different physiological SA levels are obtained by selecting the posterior-surface conic constant while preserving physiological LCA. Longitudinal chromatic aberration is evaluated from the paraxial vergence of the exit-pupil wavefront of the complete optical system and referenced to the spectacle plane of the physiological reference eye. When implanted with IOLs spanning clinically relevant dispersion ranges, the proposed model reproduces the pseudophakic LCA of the ANSI Physiological benchmark over 400-700 nm, with deviations below 0.02 D for a high-Abbe IOL and 0.06 D for a low-Abbe IOL. Polychromatic MTF analysis showed trends consistent with the residual differences in LCA across model eyes when the complete optical system was considered. These results provide a standards-compliant framework for chromatic validation of IOL test benches under physiologically relevant conditions.