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Definitions needed for EDOF IOLs, related visual disturbances
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VIENNA — A clearer definition of what extended depth of focus lenses are or should be is needed because currently, within a broad and not well-defined category of EDOF, “apples and oranges and bananas are compared,” according to one key leader in premium IOLs.
“Companies call many of the new lenses EDOF because EDOF is a very hot topic now, but we have completely different kinds of lenses under this name,” Gerd Auffarth, MD, PhD, told Healio.com/OSN at the European Society of Cataract and Refractive Surgeons meeting.
Within this broad and unclearly defined category, there are diffractive lenses that are essentially bifocal but cover the near and intermediate range. There are low-add refractive lenses, such as the Lentis Comfort with 1.5 D near addition, and the pinhole lens, “which is truly EDOF because the small aperture creates a certain depth of focus,” Auffarth said. There are other approaches, such as the Sifi Mini Well, which uses wavefront technology for enhancing depth of focus.
“We created this concept of EDOF when intermediate visual acuity started to become more important. We developed implants that could potentially offer more than pure near and distance vision and called them EDOF. But there is no clear idea of what EDOF actually is,” he said.
Another area where clearer definitions are needed is the broad category of visual disturbances caused by multifocal and EDOF lenses.
“Some people refer to them as dysphotopsia, which is easily confused with negative dysphotopsia that is a completely different form of halos and glare,” Auffarth said. “We need to differentiate between these different types of visual disturbances, taking into account confounders such as dry eye, and to standardize testing methods.”
It will be the task of ophthalmological societies to work on categorization and new, clearer terminology, he said. – by Michela Cimberle
Disclosure: Auffarth reports he receives research grants, travel and lecture fees from premium IOL manufacturers but is not a paid consultant for any of the companies.