Topography and Longitudinal Chromatic Aberration characterizations of Refractive-Diffractive Multifocal IOLs

Purpose

Most optical systems present chromatic aberration quantified along the optical axis by the longitudinal chromatic aberration (LCA). LCA is controlled by the biomaterial Abbe number combined with diffractive effects, driven by the IOL topography. This paper experimentally aims at describing in vitro the effect of LCA in diffractive multifocal IOLs, with the help of dedicated optical benches and topographic characterization.
Setting

Centre Spatial de Liege.
Design

Optical and topology analysis of various Multifocal diffractive intraocular lenses.
Methods

Seven diffractive multifocal lenses, available on the market and exhibiting different diffractive profiles, made from various biomaterials, were characterized under different wavelengths.
Results

Through-focus Modulation Transfer Function (MTF) curves and IOL diffraction efficiency depends on the incident light wavelength. In this paper, we investigated the topology properties of various Multifocal intraocular lenses and correlated their characteristics to their optical behavior for various wavelengths. Chromatic properties and their origins were then compared. As expected, diffractive and refractive effects were found to act in opposite ways, and could be partially or completely compensated.
Conclusions

The longitudinal chromatic aberration of each of the lenses was evaluated in vitro. In most of the MIOLs studied, some of the foci were found to be refractive, while others were diffractive. Although the results were not extrapolated to clinical relevance , it was shown, in some of the cases, that LCA could be fully compensated.