Eyeworld

EW GLAUCOMA 64 September 2017 by Tony Realini, MD, MPH 19% of pedestrian fatalities occur in people over age 65." She and her research team conducted a study involving 129 patients with visual impairment to assess their ability to judge if they could safely cross a street against oncoming traffic. In the first analysis, the partic- ipants were divided on the basis of their self-perception of whether or not they had difficulty crossing the street. "In this analysis, we deter- mined that participants who self-re- ported having difficulties crossing the street did not make significantly more unsafe crossing decisions compared to those participants who self-reported having no difficulties," she explained. In the second analysis, partici- pants were divided according to the presence of visual field loss. "Among these patients with visual acuity impairment, those who also have visual field loss were more prone to errors in judgment regarding safe crossings," she added. Dr. Hassan summed up her find- ings: "A visually impaired person's self-perception of their crossing abil- ity appears not to affect their ability to safely cross the street. However, patients with both visual acuity and visual field loss made significantly more crossing errors than those with visual acuity loss alone." Practical impact These studies, like others before them, clearly document that glau- coma patients with visual field loss face challenges when ambulating, whether it be falls or difficulty crossing the street. While the oph- thalmologist does not have a major role in preventing falls, there may be value in simply informing glaucoma patients with visual field loss of the increased risk, with the hope that awareness may increase caution and reduce falls. EW Editors' note: Dr. Ramulu has financial interests with the National Institutes of Health and Harkcon Inc. (Freder- icksburg, Virginia). Dr. Hassan has no financial interests related to this article. Contact information de Luna: mdeluna1@jhmi.edu Hassan: shhassan@indiana.edu Ramulu: pramulu@jhmi.edu Mihailovic: amihail2@jhu.edu The severity of their glaucoma did not alter whether activity was more likely to take place at home or away from home. "There was no significant relationship between the degree of visual field loss and the relative proportion of steps taken at home versus away from home," he added. A total of 316 falls were report- ed during the study. Where they happened came as something of a surprise to the research team: De- spite taking more overall steps away from home than at home, 177 falls occurred at home while 139 took place away from home. "Steps taken at home were 54% more likely to be associated with a fall as compared to steps taken away from home," Dr. Ramulu explained. This finding was statistically signifi- cant (p=0.008). Dr. Ramulu hypothesized that perhaps people are more cautious when in relatively unfamiliar places and less so when in the familiar setting of home. One factor that may link glauco- ma with the risk of falls is balance. In FIGS, participants underwent bal- ance testing using wearable sensors to monitor stability during a series of balance tests. The investigators found that while both visual field loss and balance were independently associated with risk of falls, poor balance did not seem to explain why glaucoma patients fell. Additionally, the relationship between balance and risk of falling did not strengthen with worsening visual field loss. "The severity of visual field damage is associated with fall rates," Ms. de Luna said. "Likewise, balance parameters seemed to be able to predict fall rates among glaucoma patients. However, the association between visual field damage and falls does not appear to be signifi- cantly affected by poor balance." Crossing the street Crossing the street requires excellent gait and balance, as well as adequate visual function and judgment, to avoid both falls and being struck by a vehicle. "Pedestrian fatalities account for 15% of all road fatalities," said Shirin Hassan, BAppSc(Optom), PhD, FAAO, Indiana University, Bloomington, Indiana. "Overall, slower when lighting becomes dim. The effect of visual field loss on gait is more pronounced when transi- tioning from bright to dim lighting. Patients with more advanced visual field loss walk more slowly, they take smaller steps—they are a lot more cautious in dim lighting." FIGS study To better assess the relationship between glaucoma and the risk of falling, Dr. Ramulu and colleagues designed and conducted the Falls in Glaucoma Study (FIGS). "FIGS is a 3-year prospective co- hort study," Dr. Ramulu explained. Funded in part by the National Institutes of Health, FIGS enrolled 245 patients with glaucoma age 60 or older. Approximately half were male, the average age was 70 years at enrollment, the average mean deviation of the visual field in the better eye was –4 dB, and subjects were followed for an average of 24.8 months. Participants wore a device clipped to the belt like a pager that featured both an accelerometer and a GPS monitor. The device tracked the number of steps taken and where they were taken. FIGS participants were not sed- entary seniors. "They averaged 1,738 steps per day at home and 2,064 steps per day away from home," Dr. Ramulu said. W hen evaluating our pa- tients with glaucoma, we focus on glauco- ma's effects on the optic nerve and the visual field. We don't always think about the broader effects of glauco- ma on our patients' overall systemic health. Falls are a good example. The relationship between falls and glaucoma was discussed by several researchers at the 2017 Association for Research in Vision and Ophthal- mology annual meeting. Falls in glaucoma "Falls are a leading cause of death in people over age 65, and both vision and balance are known risk factors for falls," said Regina de Luna, an undergraduate student at Johns Hopkins University, Baltimore. Pradeep Ramulu, MD, Johns Hopkins University, agreed. "Glau- coma is the leading cause of irrevers- ible visual field loss in the elderly and is associated with an increased risk of falling compared to normally sighted individuals," he said. The increased risk of falling may be associated with changes in gait that accompany the visual manifes- tations of glaucoma. "People with impaired visu- al acuity adopt a cautious gait," explained Aleksandra Mihailovic, a biostatistician at Johns Hopkins University. "People walk slower as their vision gets worse and even Risk of falling is real for glaucoma patients Presentation spotlight

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