Eyeworld

EW GLAUCOMA 118 September 2015 history of falls." The virtual reality test was much more predictive of the history of falling than conven- tional visual field testing, he said. This was not just a trivial dif- ference. "I was surprised by the fact that the difference in performance was substantial," Dr. Medeiros said. "Because when you think about the way we follow and monitor patients with glaucoma, it is based on the conventional visual field test." But practitioners may want to reconsider this, taking into account that per- haps the conventional visual field test is too simplistic and doesn't translate well in the way that pa- tients use their vision for everyday tasks, he said. Real-world perspective Clinically speaking, this means that practitioners need to develop better ways of assessing how a glaucoma patient's vision affects his ability to perform everyday tasks, Dr. Medeiros said. "The conventional tests that we do are not very good surrogates for the patient's ability to do things," he said. He believes that practitioners haven't taken full advantage of the progress that has been made in tech- nology over the past decades. "We have had tremendous progress in the availability of technologies like virtual reality," he said. "However, we have yet to take full advantage of these technologies in improving our ways of assessing visual impairment and its impact on everyday life. That's one of the purposes of the work that I have been conducting." Dr. Medeiros' lab has been working on subsequent studies to validate the hypothesis that the dy- namic visual testing would be more important to consider in predicting falls. "Now that we've validated that, we're moving on to subsequent studies," he said. "What we're trying to do is develop metrics and simple tests that can be used to predict a history of falls and that could be used routinely by physicians." EW Editors' note: Dr. Medeiros has no financial interests related to this article. Contact information Medeiros: fmedeiros@ucsd.edu by Maxine Lipner EyeWorld Senior Contributing Writer only requires you to be able to see a white dot on a white background." This is very different from the dy- namic way that vision is used on an everyday basis, he said. Dynamic testing "We speculated that perhaps we were not evaluating functional performance very well in patients with glaucoma," Dr. Medeiros said. "We thought that testing vision in a dynamic environment could provide a better way to assess its impact on the ability of patients to perform ev- eryday tasks. Such tests may help us better understand the relationship between glaucoma and risk of falls." To simulate an immersive environment, investigators came up with the idea of using head-mount- ed virtual reality goggles. Included in the study were 42 patients with glaucoma and 38 control subjects. Investigators began by assessing the patients on a force platform to measure their balance. "They had to stand on the platform for a few minutes while we presented visual stimuli," Dr. Medeiros said, adding that when presented with visual stimuli such as a tunnel or rotational stimulus, patients felt as if they were actually moving, although they were stationary. Because the body feels as if it is moving, the patient then begins to make some movements to compensate in order not to fall. These were picked up by the force platform, he explained. Using this technique, the pa- tients' balance was assessed under different conditions. "We noticed that the responses of patients with glaucoma were much more erratic than those of healthy subjects," Dr. Medeiros said. Investigators also looked into the patients' history of falls using a standardized questionnaire. "We collected that information and evaluated the relationship with the new metrics that we developed," Dr. Medeiros said. "From the large amount of data that we got from the force platform, we could summarize their abilities to maintain balance by a metric that we developed, which we found was very predictive of the But do traditional visual field tests tell the whole story? A recent study published in Ophthalmology considered how those with glau- coma and others would fare when tested with a dynamic virtual reality approach. Investigators decided to launch the study after noticing that the link between a history of falls and conventional static visual field testing only seemed to be tenuous, Dr. Medeiros said. "What we noticed was that this relationship was weak, which is probably explained by the fact that standard perimetry does not measure very well the way we use vision routinely," he said. "Stan- dard perimetry is a static test that How dynamic technology helps identify those at risk for falls F alling can be common in the older population, with those suffering from glaucoma at even greater risk, according to Felipe A. Medeiros, MD, PhD, professor of ophthalmology and director of the Visual Performance Laboratory, University of California, San Diego. "From 20 to 30% of people older than 65 have at least one fall per year, and some studies have shown glaucoma patients to have a signifi- cantly higher rate," he said. Glaucoma patients balanced on the virtual edge Testing vision in a dynamic environment could provide a better way to assess glaucoma's impact on the ability of patients to perform everyday tasks. To simulate an immersive environment in this study, investigators used head-mounted virtual reality goggles.

• Cover