Optical quality of aspheric toric intraocular lenses at different degrees of decentering

To analyze the optical quality of aspheric toric intraocular lenses (IOLs) at different degrees of decentering.

Wavefront aberrations of Acrysof IQ Toric IOLs (SN6AT3, SN6AT4, and SN6AT5; Alcon Laboratories Inc, Fort Worth, TX, USA) for different powers (15.00, 20.00 and 23.50 diopters [D]) and for different degrees of decentering (diagonal, horizontal, and vertical decentering of 0.3 and 0.6mm) were measured in vitro at 3- and 5-mm pupils. The Zernike coefficients of trefoil, coma, tetrafoil, secondary astigmatism, and spherical aberration were evaluated. The point spread functions (PSFs) and modulation transfer function (MTF) of each IOL evaluated were calculated from the wavefront aberrations.

Coma aberration increased significantly with IOL decentration. Statistically significant differences were found between centered and all decentered positions in coma aberration (p < 0.05). Although, we only found visible differences between centered and decentered positions in PSF images and MTF curves for horizontal and vertical 0.6 mm of decentering at 3- and 5-mm pupil.

Despite the coma increment, these values were clinically negligible and have no effect on visual performance, except for vertical and horizontal 0.6 mm of decentering, which could have a negative effect on visual quality.