Eyeworld

58 | EYEWORLD | SEPTEMBER 2021 R EFRACTIVE References 1. Waring GO, Rocha KM. Char- acterization of the dysfunctional lens syndrome and a review of the literature. Curr Ophthalmol Rep. 2018;6:249–255. 2. Mercer RN, et al. Future trends in presbyopia correction. J Refract Surg. 2021;37:S28–S34. Relevant disclosures Bafna: Alcon, CorneaGen, Carl Zeiss Meditec Waring: Ace Vision Group, Allergan, Johnson & Johnson Vision could have some degree of dysphotopsias, and it doesn't give as much near vision, Dr. Bafna said. "What's unique about Vivity is it's the first and only non-diffractive IOL, so it does not split light," Dr. Bafna said. "It has a dysphotopsia profile that's similar to other monofocal lenses and gets distance and intermediate and some functional near while avoiding dysphotopsia." Dr. Waring said he thinks one of the most exciting areas of presbyopia surgery is lens replacement procedures. "We now have fem- tosecond lasers, which are intuitive to patients looking for laser vision correction," he said. There is also a selection of presbyopia-correct- ing refractive implants that can really deliver on both quantity and quality of vision, he added, as well as a rich pipeline of implants in develop- ment that have great promise. "We think of presbyopia as one of the emerging subspecialties within the specialty of refractive surgery and refractive cataract surgery," Dr. Waring said, adding that a large portion of his practice is dedicated to the art and surgical management of presbyopia. He said there are more diagnostics geared toward diagnosing the different stages of the dysfunc- tional lens, which will help clinicians make a better decision in terms of what type of treat- ment is appropriate. Pharmacological options Another presbyopia treatment in development is the use of eye drops, though no product is currently approved by the FDA. Dr. Waring served as the principal investi- gator for the Allergan clinical trial for a novel eye drop for the treatment of presbyopia. If approved, it will be the first eye drop to help reduce dependence on reading glasses and con- tact lenses for the treatment of presbyopia. He said there are a number of other drops in development as well, though other products are earlier in the development process than the Allergan one. "These drops will likely serve as a gate- way to help the public and eyecare providers understand what presbyopia is," he said. "It is a naturally ubiquitous condition that can be helped, and they will have an alternative to reading glasses, bifocals, and contact lens- es. These could be perfect for those that are recently experiencing the earlier stages of lens dysfunction." contrast sensitivity and the potential for night vision disturbances. Dr. Bafna said that PRESBYOND is used a fair amount outside the U.S., and he wishes it was available here. When you do excimer ablation, the goal is to reduce spherical aberration because it helps patients to see more crisply at a particular point of focus, Dr. Bafna said. If you increase spherical aberration, it increases depth of field. PRESBYOND uses the concept of increasing spherical aberration with proprietary abla- tion techniques that increase overall spherical aberration on the cornea. It also has an element of monovision that helps increase the depth of field and gives patients near and distance vision. Dr. Bafna noted that PRESBYOND is dif- ferent from traditional monovision because it's blended vision. The distance vision is good, there is decent intermediate, and the near eye gets more intermediate and more near. There's not too much difference between the two eyes. Lastly, Dr. Bafna discussed lens-based options. "What's nice about working at the lens level is you're going where the problem is. When you try to correct it at the corneal level, you're not focusing where the problem is," Dr. Bafna said, explaining that as the lens continues to get worse, cornea-based options lose more of their effect. With lens-based options, you either wait for the patient to develop a cataract or you perform a refractive lens exchange before a cataract develops, he said. There are a lot of different lenses in de- velopment, Dr. Bafna said. Surgeons currently have access to multifocal and extended depth of focus lenses. "In the past, most multifocal lenses we employed were bifocal lenses," he said. "When PanOptix [Alcon] got approved in the U.S., that changed things to where we got to the same level as the rest of the world." He added that more trifocal lenses are being developed, and these tend to be more effective, covering distance, intermediate, and near vision. The main downside of multifocal lenses is they use a diffractive optic that splits light, so patients will have some dysphotopsia, especially at night. As the technology has improved, the amount of dysphotopsia has been reduced, he added. Extended depth of focus lenses include the Symfony (Johnson & Johnson Vision) and Vivity (Alcon). Symfony has a diffractive optic, which continued from page 57

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