Spatio-Chromatic Vision With Multifocal Intraocular Lens

To show the modification of the visual acuity (VA) experienced by patients implanted with multifocal diffractive intraocular lenses (IOLs) when looking at far and near distances under different colour illumination. To provide a physical interpretation.

Applied Optics and Image Processing Research Group. Universitat Politècnica de Catalunya – BarcelonaTech, Spain

Hospital de Mataró, Consorci Sanitari del Maresme, Spain.

Presbit clinic. Sabadell, Spain

Creu Groga clinic. Calella, Spain

Eurolaser clinic. Mataró, Spain

Optical-bench (in-vitro) experiment: A model eye illuminated with red R(625nm), green G(530nm) and blue B(455nm) lights was used for the optical characterization of two trifocal diffractive IOLs (AT LISA Tri (Zeiss) and FineVision (PhysIOL)). Metrics used: Longitudinal chromatic aberration (LCA) and through focus (TF) analysis of energy efficiency (EE) and area under the modulation transfer function (MTFa).

Clinical (in-vivo) experiment: Visual acuity (VA) assessment at far (0.0 D) and near (-3.0 D) under white (W) and R, G, B lights. Forty pseudophakic patients (40 eyes) implanted with the same IOLs analysed in-vitro were examined.

The diffractive nature of the add power profile of the two multifocal IOLs analyzed has an impact on the VA. It can be detected when changing the spectral band of the illumination and the vision distance. The visual quality under R and B lights shows asymmetry: red predominance at far while blue predominance at near. Although after LCA compensation in far vision, subjects significantly improved their VA under B light, the sole influence of LCA is insufficient to explain such an asymmetry. The main reason is found in the wavelength dependence of the energy efficiency exhibited by zeroth- and first-order diffractive IOL profile, also evidenced through the distributions of energy measured in the optical-bench (in-vitro) experiment.

The alterations in the spatio-chromatic vision produced by multifocal diffractive IOLs, with significant changes in resolution depending on the object distance and the spectral band of the illumination, can be detected with the methods and materials of ordinary clinical examination. Such alterations in pseudophakic patients could affect their visual perception of colour textured objects and the performance of tasks concerning local variations of colour and observation distance.