Longitudinal Chromatic Aberration and Polychromatic Image Quality Metrics of Intraocular Lenses

To measure longitudinal chromatic aberration (LCA) of various intraocular lenses (IOLs) and to assess LCA effects on polychromatic image quality with a focus on multifocal IOL designs.

The LCA values of four multifocal IOL models (three diffractive models: AT LARA 829MP and AT LISA 809M [both from Carl Zeiss Meditec AG, Jena, Germany] and Restor SN6AD1 [Alcon Laboratories, Inc., Fort Worth, TX] and one refractive model [Mini Well Ready; SIFI Medtech, Sant'Antonio, Italy]) were compared with that of their monofocal counterparts. Optical properties were assessed using an optical bench device with spectral filters. LCA was calculated as a difference of a lens power at 480 and 644 nm. The optical quality was evaluated objectively by means of modulation transfer function metrics.

At far, LCA of an aphakic model eye (1.04 diopters [D]) increased with the AT Lisa, Restor, and Mini Well IOLs to 1.40, 1.91, and 1.27 D, respectively, but decreased to 0.78 D with the AT Lara IOL. The AT Lisa and Restor IOLs showed comparable results with their monofocal platforms. A near-focus LCA decreased only in the diffractive IOLs. At far, the polychromatic modulation transfer function was reduced in all IOLs, but LCA effects were attenuated at near.

Multifocal IOLs and their monofocal counterparts show similar material dispersion. Multifocal diffractive IOLs proved effective in reducing LCA, but the efficiency of the LCA correction differed depending on the optical design. LCA adversely affects the polychromatic image quality. [J Refract Surg. 2018;34(12):832-838.].