Eyeworld

EW RETINA 144 by Maxine Lipner EyeWorld Senior Contributing Writer the patients' scotomas ranged from 7 to 25 degrees in diameter and were located either above or below the patients' gaze points. In a study published in the March 2013 issue of JAMA Ophthalmology in which Dr. Bowers also took part, she reported results for patients with scotomas that were either to the left or to the right of the gaze point. To safely examine how patients might react to such situations, inves- tigators employed a driving simula- tor and compared reactions of those with AMD to those of controls. Use of the driving simulator enabled investigators to give exactly the same test to everyone, as well as to program exactly where pedestrians would appear, Dr. Bowers explained. In this current study, the sizes of vision. "The reason that this is rele- vant here in the U.S. is that even if people don't meet the 20/40 (acuity) requirement, they may still be able to drive with a restricted license," Dr. Bowers said, adding that acuity could be as low as 20/200 with a re- stricted license in some states. Those with AMD who have 20/200 vision are going to have a fairly sizeable central scotoma. Focusing on reaction times behind the wheel and scotomas D riving for age-related mac- ular degeneration (AMD) patients with scotomas may be problematic, according to Alex Bowers, PhD, assistant professor of ophthal- mology, Harvard Medical School, and assistant scientist, Schepens Eye Research Institute, Massachusetts Eye and Ear, Boston. Those with central visual field loss from the condition may experience delayed reaction times when it comes to avoiding pedestrian hazards, she reported in a study published in the September 2015 issue of PLOS One. Dr. Bowers and colleagues, Eli Peli, OD, professor of ophthalmol- ogy, and Matthew Bronstad, PhD, instructor in ophthalmology, were spurred to examine the issue by concerns about what driving with scotomas could mean for many. "AMD is an eye condition where the older you get, the more likely you are to have the condition," Dr. Bowers pointed out, adding that with patients living longer than ever, there is a worry about what this could mean for those who continue to drive. In the U.S., regulations regard- ing visual requirements for driving vary by state and usually only take into account the need for visual acuity to be around 20/40. "None of the states that I'm aware of in the U.S. say anything about the integ- rity of the central visual field," Dr. Bowers said. "But other countries like the U.K. and Australia do—they have a clause that says there should be no significant scotomas or field loss within the central 20 degrees or so." This speaks to the fact that, along with reduced visual acuity, patients with AMD usually also have a central scotoma. "But that's not often taken into account in evaluat- ing visual fitness to drive here in the U.S.," Dr. Bowers said. Studying the effect of scotomas The idea was to consider how pa- tients' ability to detect and respond to potential road hazards while driv- ing might be impaired if they have a blind area in the center of their In the driver's seat with AMD April 2016 Patients with AMD who have blind spots tend to have slower response times to hazards in the road. Driving simulator used in the study Source: Peter Mallen, Schepens Eye Research Institute

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