Abstract
Purpose :
To compare image quality of two aspheric IOL designs using Optical Raytracing under conditions of tilt, decentration and minor defocus.
Methods :
An optical raytracing model was created in Zemax OpticStudio® using an Liou and Brennan model eye with spherical aberration (SA) of 0.21µm at 5mm. A simulation was performed with minor amounts tilt (5°) and decentration (0.25mm) and defocus (-0.25, +0.25D). The first type of IOL is designed to be free of spherical aberration (SA), similar to MX60E IOL from Bausch and Lomb, Inc. The second IOL is designed to have negative SA (similar to SN60WF IOL, Alcon). Both subjective (image resolution) and objective (Modulation Transfer Function, MTF) were simulated to compare image quality between the two types of aspheric IOL designs.
Results :
Under conditions of tilt and decentration, the model eye with zero SA IOL showed less degradation of image quality (MTF, image resolution at the retina) when compare to the negative SA IOL. When the addition of mild defocus (-0.25, +0.25D) the zero SA IOL still performed better with less image degradation. Wavefront analysis shows that coma was larger with negative SA IOL, which mainly accounted for the observed worse image resolution.
Conclusions :
The optical raytracing model demonstrated that an IOL with zero spherical aberration is more resistant to minor amounts of tilt, decentration, and defocus with better image quality resolution compare to an IOL with negative spherical aberration.
This is a 2020 ARVO Annual Meeting abstract.