Spectral performance of a trifocal intraocular lens

Abstract

We describe a hybrid refractive-diffractive trifocal design for an intraocular lens (IOL) and experimentally measure the light distribution among the distance, intermediate and near foci, with three different wavelengths, in order to determine its power, energy efficiency and spectral behaviour, such as the Longitudinal Chromatic Aberration (LCA). A commercial trifocal IOL is tested in-vitro in optical bench and the Through-Focus Energy Efficiency (TF-EE) assessed with red, green and blue illuminations. The results show a correspondence between the three peaks obtained in the TF-EE curve with the theoretical trifocal design, with an unbalanced energy distribution among the foci. The LCA at the distance focus is influenced only by the refractive part of the IOL, it has a positive value, while at the intermediate and near foci the diffractive profile also have an influence, having null and negative LCA values respectively. There is a good agreement between the theoretical description of the trifocal IOL and the experimental values of the TF-EE and LCA.