Posters

Spherical and aspheric toric intraocular lenses: optical quality comparison

Poster Details

First Author: C.Pérez-Vives SPAIN

Co Author(s):    T. Ferrer-Blasco   D. Madrid-Costa   C. Albarrán-Diego   R. Montés-Micó     

Abstract Details

Purpose:

To measure in vitro and compare the optical quality of spherical and aspheric toric intraocular lenses (IOLs) at different IOL powers and for two pupil diameters.

Setting:

Valencia University Clinic, Spain.

Methods:

Wavefront aberrations of Acrysof Toric (SN60T3, SN60T4 and SN60T5) and 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]) 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) of each IOL evaluated were calculated from the wavefront aberrations. The PSF images also were calculated from the IOLs wavefront aberrations adding cornea's wavefront aberrations at 3- and 5-mm pupil to simulate the optical quality after their implantation.

Results:

Spherical toric IOLs showed positive and aspheric toric IOLs negative spherical aberration values. Statistically significant differences were found in spherical aberration RMS values between spherical and aspheric IOLs for both pupil sizes evaluated (p<0.05). Aspheric toric IOLs showed higher spherical aberration RMS values. Although, we did not find visible differences in PSF images between both IOL designs at 3-mm pupil, they became apparent at 5-mm pupil. The PSFs corresponding to the aspheric toric IOLs showed more spread out than the PSFs corresponding to the spherical toric IOLs at 5-mm pupil. However, when corneal aberrations were added, aspheric toric IOLs showed better PSF images and a wavefront pattern more uniform than spherical toric IOLs at 5-mm pupil.

Conclusions:

Spherical and aspheric toric IOL designs showed good optical quality for both pupil sizes. At 5-mm pupil the optical quality was higher for spherical IOLs than aspheric IOLs when the IOLs are measured in vitro. However, when the corneal wavefront aberrations are considered, aspheric toric IOLs showed better optical quality than spherical toric IOLs; due to the compensation between aspheric toric IOL negative spherical aberration and corneal positive spherical aberration. At 3-mm pupil, there were not differences in optical quality between both IOL designs measured in vitro and when the corneal aberrations are added. FINANCIAL INTEREST: NONE