Eyeworld

by Steven J. Dell, MD Presbyopia correction without compromise: How close are we? Three tipping points in refractive cataract surgery O ur current surgical tech- niques for the man- agement of presbyopia include 2 good technol- ogies: multifocal and accommodating IOLs. According to the 2014 ASCRS Clinical Survey, presbyopia-correcting IOLs account for only 7.2% of procedures in the U.S. Comparatively, 22% of patients receive monovision. 1 As a group, are we accurately understanding the goals and needs that our patients have? Are we achieving those goals? The 2014 ASCRS Clinical Survey presented a scenario: If a multi- focal IOL patient has no residual refractive error and an excellent ocular surface, what do you think the chances are that they will have functionally significant visual aber- rations at night? Both U.S. and non- U.S. surgeons responded similarly —5.7% overall, with slightly more U.S. surgeons believing patients will have functionally significant visual aberrations (6.0%) than non-U.S. surgeons (5.5%). 1 Similar results were found when we asked the ques- tion about accommodating IOLs. We asked about the lowest amount of residual astigmatism that's accept- able to leave for these patients. Both U.S. and non-U.S. physicians responded 0.63 D. A growing body of research is demonstrating that the higher the level of residual error, the lower the visual quality, so 0.63 D might not be the benchmark that physicians want to aim for. 2 Today's patients demand great solutions. For patients, that means clear vision at near, intermediate, and far; no contrast loss; and low/ no problems with glare or halos. For physicians, "great" means high patient satisfaction, reliable out- comes, and no significant additional chair time. Can we achieve those goals with the current or next generation of presbyopia-correcting IOLs? Can we—or how can we—match the risk profile of a monofocal IOL? That's the ultimate goal. Next-generation IOLs The next generation of presbyopia -correcting IOLs include low power multifocal IOLs that focus on inter- mediate and distance vision using the same optical concepts as current multifocals. These have the poten- Steven J. Dell, MD Dr. Dell is director of refractive and corneal surgery at Texan Eye in Austin, Texas, and medical director of Dell Laser Consultants. He can be contacted at steven@dellmd.com. tial for better contrast sensitivity, and they have the potential to be mixed with a high power add in one eye and a lower power add in the other eye. A new category of PC-IOLs, the so-called expanded elongated depth of focus IOLs, use a different optical strategy. They elongate the focal point as opposed to providing multiple foci. These lenses achieve that without optical compromise. A new PC-IOL, the AcrySof 2.5, directs more of its light energy to distance and less to near, resulting in a lens that's truly designed for intermedi- ate vision. This lens is not available in the U.S., but when evaluating the defocus curve for this lens, the effec- tive add is about 1.75 D compared to about 2.25 D with the ReSTOR 3.0. 3 Figure 1. Refractive optic: Short wavelength light bent more Figure 2. Diffractive optic: Short wavelength light bent less Figure 3. Combination optic: Corrects for chromatic aberration

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