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Reducing pseudophakic ametropia to drive improved refractive IOL outcomes Supplement to EyeWorld September 2013 H istorically, cataract surgeons have been spoiled in terms of patient satisfaction, ac- cording to David F. Chang, MD, clinical professor of ophthalmology, University of California, San Francisco. Dr. Chang and Richard S. Hoffman, MD, clinical associate professor, Casey Eye Institute, Oregon Health & Science University, Portland, Ore., co- chaired a symposium on keratorefractive surgical enhancement of refractive IOL patients at the 2013 ASCRS•ASOA Symposium & Congress in San Francisco. "Who among us tires of hearing patients rave about how easy and painless the operation was; how quickly the vision improved; and how color, brightness, and uncorrected vision are so surprisingly good?" Dr. Chang said. "Indeed, we've become very accustomed to routinely ex- ceeding the expectations of our cataract patients." However, in recent years, the increas- ing confluence between cataract and refractive surgery has changed patient expectations and altered the satisfaction equation. Cataract surgeons are now able to offer a wide range of refractive IOLs and adjunctive procedures such as astigmatic keratotomy; with this in mind, even with uncomplicated surgery, patients may now be dissatisfied because their expectations for uncorrected visual function are not met. "Part of the issue is that in an effort to understand confusing concepts such as refractive error, focal point and depth of focus, many patients tend to oversimplify the value proposition," said Dr. Chang. In the U.S., since insurance already covers the cataract procedure, patients some- times assume that the additional fees they pay for a lens mean they won't need glasses to drive or read. The value of preoperative counseling to set realistic expectations thus cannot be overstated; however, tempering patient expectations addresses only part of the problem. According to Dr. Chang, the most common cause of patient dissatisfaction following any refractive IOL procedure is residual refractive error. "For instance, while 90% of our patients are typically within 1.0 D of spherical target, there may only be 75% who are within 0.5 D of their target," he said. Program chairs Participants David F. Chang, MD Richard S. Hoffman, MD Richard L. Lindstrom, MD Karl G. Stonecipher, MD Scott M. MacRae, MD William B. Trattler, MD Steven C. Schallhorn, MD Sonia H. Yoo, MD John A. Vukich, MD Warren E. Hill, MD This fact is particularly important when it comes to multifocal IOLs. Studies have shown that a large percentage of multifocal IOL patients who are unhappy with their outcomes complain of blurry vision due to residual refractive error. 1,2 In one study, 28% of eyes had residual astigmatism of 0.75 D or greater. 1 "With a monofocal IOL, 0.5 D of myopia or a small amount of astigmatism are tolerable and may actually increase depth of focus," said Dr. Chang. "However, with diffractive multifocal IOLs, the inherent loss of image contrast makes these lenses much less forgiving of the same errors." While Dr. Chang said that this is a lesson every cataract surgeon learns inevitably through experience, the phe- nomenon has been demonstrated objec- tively through optical bench testing in an elegant study conducted at the University of Rochester. This study demonstrated no- ticeable drops in image quality and depth of focus for a number of different refractive IOLs subjected to varying degrees of resid- ual astigmatism, with multifocal IOLs found to be much more sensitive to corneal astig- matism compared with monofocal IOLs. Supported in part by unrestricted grants from Alcon and Abbott Medical Optics

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