Eyeworld

EW INTERNATIONAL 74 June 2016 by Michelle Dalton EyeWorld Contributing Writer Although not available in the U.S., trifocal IOLs are showing promise in Europe T oday's cataract patients are becoming as demanding as refractive patients—and many expect both spectacle independence and astig- matic correction. Multifocal IOLs have been able to address near and distance vision, but often do not ad- dress intermediate vision, and some are not available in toric versions. But those familiar with trifocal IOLs say vision outcomes are stellar across all distances, and patient satisfaction is high. "In the U.S., it is only the Food and Drug Administration that is standing in the way of U.S. surgeons having access to these great lenses," said Richard Packard, MD, director, Arnott Eye Associates, London. Outcomes with trifocals are "clearly superior" to those with bifocal or other multifocal lenses, said Jorge Alio, MD, professor and chair of ophthalmology, University of Alicante, Spain. The benefit for patients is that "there is a true intermediate focus with trifocal lenses," with no dim- inution of near or distance vision, said Florian Kretz, MD, research assistant, Department of Ophthal- mology, University of Heidelberg, Germany, and lead surgeon, Dr. Gerl & Colleagues, Ahaus, Germany. Trifocal IOLs: Meeting patients' and surgeons' expectations Device focus The FineVision trifocal lens Source: PhysIOL In Germany, the AT Lisa tri and AT Lisa tri toric (Carl Zeiss Meditec, Jena, Germany), Micro-F FineVision and Micro-F FineVision Pod F (PhysIOL, Liege, Belgium), Acriva Reviol (VSY Biotechnology, Am- sterdam, the Netherlands), and the AcrySof PanOptix (Alcon, Fort Worth, Texas) are commercially available. None of these lenses have been approved in the U.S. The FineVision and AT Lisa are also available in toric versions, and the PanOptix is expected to have a toric version in the fall, Dr. Packard said. In Spain, the Mplus X (Oculentis, Berlin) is "varifocal and can be considered a trifocal by its defocus curve," Dr. Alio said. Causes of popularity The reasons these lenses are gain- ing popularity in Europe and why they are so appealing has to do with their optical properties and clinical interest, said Roberto Bellucci, MD, chief ophthalmic surgeon, Hospital of Verona, Italy. "Optically, trifocal lenses exploit part of the 'lost light' typical of diffractive bifocal IOLs," Dr. Bellucci said. Diffractive bifocal IOLs with a +3.5 D near add "also produce 'har- monic' foci at +7.0 D, +10.5 D, +14.0 D, and so on, that attracts about 20% of the incident light," he said. "This light is considered the lost light of these kinds of IOLs." Conversely, Dr. Bellucci said, diffractive trifocals incorporate 1 di- optric power for intermediate vision (e.g., +1.75 D), and a second double add for near vision (e.g., +3.5 D). "This way, the first harmonic focus of the intermediate dioptric power will enforce the near focus produced by the near dioptric power and will contribute to useful vision," he said. "Trifocal IOLs reduce the amount of lost light to about 14%, claimed by 1 manufacturer, and up to a surprising 10.5%, claimed by another." Clinically, Dr. Bellucci said the modular transfer function of the IOL is not impacted by the trifocality because the overall size of the halo is the same as bifocal IOLs. In short, these lenses "create a continuous focus for most pa- tients," Dr. Alio said, noting there are important differences among the available lenses in their intermediate vision, but all are "slightly less effi- cient for near and the light is more divided into the intermediate." Multifocal lenses available in the U.S., however, "are essentially bifocals with no intermediate focus if they have a reading focus," Dr. Packard said, but noted the ReSTOR 2.5 (Alcon) "is designed for distance and intermediate vision." A simi- lar effect to increase intermediate vision is used in the ZKB00 (Abbott Medical Optics, Abbott Park, Illinois) with a 2.75 add. Patient selection considerations From the patient's perspective, "trifocal IOLs provide intermediate vision without compromising near vision, and intermediate is more important to patients as our world is now dominated by computers, smartphones, and tablets," Dr. Bellucci said. In 2014, Dr. Bellucci compared toric trifocals in 11 bilaterally astig- matic patients to 11 non-astigmatic patients also implanted with the tri- focal lens (both versions were from PhysIOL). None of the patients are using spectacles for distance vision, and both groups reported a high satisfaction rate. "I've abandoned diffractive bifocal IOLs to implant only trifocal IOLs when patients want spectacle independence," he said. Patient selection for these lenses is the same as for any premium lens, Dr. Alio said. "Avoid comorbidities that could affect the macula or con- trast sensitivity, and consider patient age. I do not implant multifocal lenses in patients over the age of 80," he said. Learning curve Surgeons who are familiar with toric bifocal multifocal lenses will likely have no learning curve, Dr. Packard said. "The most important thing with all these lenses is to understand how they work so that you can advise patients as to what they will experi- ence," he said.

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