Eyeworld

I N FOCUS 48 | EYEWORLD | DECEMBER 2019 by Chiles Samaniego EyeWorld Contributing Writer is used in the nondominant eye to create phar- macological monovision. According to Dr. Vejarano, these drops subscribe to the standard theory of presby- opia—that the crystalline lens gets stiffer with age, preventing accommodation—and so in- duce a ciliary muscle spasm to bypass the factor of the crystalline lens's inflexibility. In contrast, Dr. Vejarano believes that the major cause of decreasing near vision in advancing age is a decrease in the force from the ciliary muscle— hence the sudden onset of the inability to focus, which he does not believe can be explained by the loss of crystalline lens elasticity. Dynamic accommodation Based on this theory, Dr. Vejarano developed FOV Tears as "a mix of many components," including a parasympathetic substance to generate accommodation and alpha agonists to counteract ciliary muscle spasm in a precise concentration to keep the pupil dynamic, that is more responsive to changes in light , avoiding a fixed miosis and resulting in variable accommo- dation—thus, more physiological. Dr. Alió and Dr. Vargas, explaining how FOV Tears work, wrote that while "pilocarpine stimulates accommodation and pupillary miosis, phenylephrine, nepafenac, and pheniramine stop excess pupil constriction and counteract ciliary muscle spasm, vascular congestion, and hyperemia induced by pilocarpine. Naphazo- line intensifies the relaxing effect of pilocar- pine on dilator pupillae. The synergistic effect improves near vision, preserves distance vision, and reduces side effects such as hyperemia and headaches." Dr. Alió, Dr. Vargas, and Dr. Vejarano con- ducted a pilot study using FOV Tears, published earlier this year in Ophthalmology and Therapy. 1 Using FOV Tears in 117 presbyopic patients, they looked at binocular uncorrected near visual acuity, ocular scatter index (OSI), and pupil size under photopic and mesopic conditions evaluat- ed 2 hours after binocular instillation. They found that FOV Tears "improved near vision by one or more lines (mean im- provement 0.18 lines) in 92.3% of the patients P resbyopes, in general, represent "an enormous market, and a very motivat- ed one," John Hovanesian, MD, said. "You see these people now who have presbyopia, people in their late 40s, 50s, into their 60s. These are people who are at the maximum earning potential of their lives and so they can afford surgery. They're really bothered by needing reading glasses, on the whole." Nonsurgical options for presbyopes have, to date, been limited to bifocal spectacles and contact lenses, but eye drops are just on the horizon. "There are several companies developing eye drops for the treatment of presbyopia," Mi- chael Korenfeld, MD, wrote in correspondence with EyeWorld. EyeWorld spoke with Dr. Hovanesian and corresponded with Michael Korenfeld, MD, Jorge Alió, MD, PhD, (writing with Veronica Vargas, MD), and Felipe Vejarano, MD, to get the drop on pharmacological approaches to treating presbyopia before they hit the market. Small aperture pupils Most drops in development "are based upon the principle of delivering a miotic drug in sufficient amount to trigger pupillary miosis but less or no ciliary muscle contraction," Dr. Ko- renfeld said. "By making the pupil smaller, the depth of focus is improved and so is the ability to resolve things that are in the intermediate and near range." Essentially, pupils are turned into small aperture optics. This is the case with the drops being de- veloped by Allergan (AGN-199201 and AGN- 190584), Orasis Pharmaceuticals (CSF-1), and Presbyopia Therapies (PRX-100), Dr. Hova- nesian said. Allergan's presbyopia eye drops, he added, may end up being the first to enter the U.S. market, which may see the first drops sometime in the next 2 years. Dr. Vejarano noted that most of these agents induce what he called a spasmodic—as opposed to dynamic—accommodation, result- ing in a myopic shift to improve near vision. The presbyopia-treating eye drop in these cases EXAMINING PRESBYOPIA TREATMENTS Getting the drop on presbyopia At a glance • Drops for presbyopia correc- tion typically work by inducing miosis to extend the range of focus and can be used as pharmacological monovision. • Some drops in development work based on opposing theories of presbyopia in an attempt to restore or retain the eye's ability to accommodate. • Some doctors think drops will have their own niche role in a presbyopia-treating practice, potentially even driving surgery forward by allowing patients to "test the waters" of presbyopia treatment. About the doctors Jorge Alió, MD, PhD University Miguel Hernandez, Vissum Instituto Oftalmologico Alicante, Spain John Hovanesian, MD Harvard Eye Associates Laguna Hills, California Michael Korenfeld, MD Comprehensive Eye Care Ltd. Washington, Missouri Veronica Vargas, MD University Miguel Hernandez, Vissum Instituto Oftalmologico Alicante, Spain Felipe Vejarano, MD Fundación Oftalmológica Vejarano Popayán, Colombia

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