Multifocals versus Crystalens (single optic accommodating intraocular lens) with Corneal Astigmatism

The question for all eye surgeons currently is, “What is the best IOL (intraocular lens) to use on my patients who had previous refractive surgery?”
Here are some papers that are helping to answer this question.

In short, it depends on how much remaining astigmatism is present. If there is more than 0.75D of astigmatism, generally a multifocal IOL would not be recommended, unless this astigmatism can be corrected. Even then, there is a big controversy if multifocal seriously decrease contrast sensitivity in our post LASIK patients.
J Cataract Refract Surg. 2012 Oct;38(10):1724-33. doi: 10.1016/j.jcrs.2012.05.032. Epub 2012 Aug 15.

Impact of corneal aberrations on through-focus image quality of presbyopia-correcting intraocular lenses using an adaptive optics bench system.


Flaum Eye Institute, University of Rochester, Rochester, NY 14624, USA.



To measure the impact of corneal aberrations on the through-focus image quality of presbyopia-correcting intraocular lenses (IOLs) using an adaptive optics IOL metrology system.


Flaum Eye Institute, University of Rochester, Rochester, New York, USA.


Experimental study.


An adaptive optics IOL metrology system comprising a model eye, wavefront sensor, deformable mirror, and an image-capturing device acquired through-focus images of a letter chart with 3.0 mm and 5.0 mm pupil diameters. The system was used to induce corneal astigmatism and higher-order aberrations (HOAs) in previously measured pseudophakic presbyopic eyes. A single-optic accommodating IOL (Crystalens HD (HD500), an apodized (Restor +3.0 diopter [D] SN6AD1) and full-aperture (Tecnis ZM900) diffractive multifocal IOL, and a monofocal IOL (Acrysof SN60AT) were evaluated. Image quality was quantified using the correlation-coefficient image-quality metric.


The single-optic accommodating IOL and monofocal IOL performed similarly; however, with a 3.0 mm pupil, the former had better intermediate (1.50 D) image quality. The multifocal IOLs had bimodal through-focus image quality trends. Corneal astigmatism reduced through-focus image quality and depth of focus with all IOLs; however, the multifocal IOLs had the most severe decline in depth of focus. Ocular spherical aberration had the strongest impact on image quality when typical pseudophakic corneal HOAs were present.


The uncorrected corneal astigmatism and HOAs in pseudophakic eyes significantly affected through-focus performance of presbyopia-correcting IOLs. Although multifocal IOLs significantly increased depth of focus, this benefit diminished when more than 0.75 D astigmatism remained uncorrected. Residual ocular spherical aberration had a significant effect on image quality in the presence of other corneal HOAs.
Copyright © 2012 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.
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