Posters

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

Poster Details

First Author: C.Pérez-Vives SPAIN

Co Author(s):    T. Ferrer-Blasco   S. García-Lázaro   C. Albarrán-Diego   R. Montés-Micó     

Abstract Details

Purpose:

To analyze the optical quality of aspheric toric intraocular lenses (IOLs), measured in vitro, for three powers and at different degrees of decentering.

Setting:

Valencia University Clinic, Spain.

Methods:

Wavefront aberrations of Acrysof IQ Toric IOLs (SN6AT3, SN6AT4 and SN6AT5; Alcon Laboratories Inc, Fort Worth, Texas 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 0.6-mm) 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 was calculated from the wavefront aberrations.

Results:

All IOLs evaluated had negative values of spherical aberration and all showed negligible amounts of other aberrations in centered position. Regarding to the effect of decentering, we found statistically significant differences in vertical coma for diagonal and vertical 0.3 and 0.6 mm decentration and in horizontal coma for diagonal and horizontal 0.3 and 0.6 mm decentration, comparing with centered position at all IOL powers and both pupils evaluated (p<0.05). Therefore, coma aberration increased with IOL decentration and this increment was greater for higher pupil sizes. No statistically significant differences were found in other Zernike coefficient RMS values evaluated between centered and any decentered position for any IOL powers evaluated (p>0.05). The differences in the PSF images between centered and decentered positions were minimal for all refractive powers at 3-mm pupil. However, at 5-mm pupil, the PSFs images for horizontal and vertical 0.6 mm of decentering are more spread out than the other ones for all powers evaluated. The MTF curves also showed lower optical quality for horizontal and vertical 0.6 mm of decentering at 3- and 5-mm pupil and for every IOL powers evaluated.

Conclusions:

This study shows good optical quality of aspheric toric IOLs at centered position. IOL decentering affected the optical quality increasing coma aberration for all decentered position evaluated. Despite this coma increment, it is expected that these values will be 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. This fact could attribute to the fact that in this condition the IOL edge appears, because of the IOL optic is 6-mm. FINANCIAL INTEREST: NONE