Alex A. Black

Risk of Falls, Injurious Falls, and Other Injuries Resulting from Visual Impairment among Older Adults with Age-Related Macular Degeneration

PURPOSE Age-related macular degeneration (AMD) is the leading cause of irreversible visual impairment among older adults. This study explored the relationship between AMD, fall risk, and other injuries and identified visual risk factors for these adverse events. METHODS Participants included 76 community-dwelling individuals with a range of severity of AMD (mean age, 77.0 ± 6.9 years). Baseline assessment included binocular visual acuity, contrast sensitivity, and merged visual fields. Participants completed monthly falls and injury diaries for 1 year after the baseline assessment. RESULTS Overall, 74% of participants reported having either a fall or a non-fall-related injury. Fifty-four percent of participants reported a fall and 30% reported more than one fall; of the 102 falls reported, 63% resulted in an injury. Most occurred outdoors (52%), between late morning and late afternoon (61%) and when navigating on level ground (62%). The most common non-fall-related injuries were lacerations (36%) and collisions with an object (35%). Reduced contrast sensitivity and visual acuity were associated with increased fall rate, after controlling for age, sex, cognitive function, cataract severity, and self-reported physical function. Reduced contrast sensitivity was the only significant predictor of non-fall-related injuries. CONCLUSIONS Among older adults with AMD, increased visual impairment was significantly associated with an increased incidence of falls and other injuries. Reduced contrast sensitivity was significantly associated with both increased rates of falls and other injuries, while reduced visual acuity was only associated with increased fall rate. These findings have important implications for the assessment of visually impaired older adults.

Inferior field loss increases rate of falls in older adults with glaucoma.

Purpose. To examine the visual predictors of falls and injurious falls among older adults with glaucoma. Methods. Prospective falls data were collected for 71 community-dwelling adults with primary open-angle glaucoma (mean age, 73.9 ± 5.7 years) for 1 year using monthly falls diaries. Baseline assessment of central visual function included high-contrast visual acuity and Pelli-Robson contrast sensitivity. Binocular integrated visual fields were derived from monocular Humphrey Field Analyzer plots. Rate ratios (RR) for falls and injurious falls with 95% confidence intervals (CIs) were based on negative binomial regression models. Results. During the 1-year follow-up, 31 (44%) participants experienced at least one fall and 22 (31%) experienced falls that resulted in an injury. Greater visual impairment was associated with increased falls rate, independent of age and gender. In a multivariate model, more extensive field loss in the inferior region was associated with higher rate of falls (RR, 1.57; 95% CI, 1.06 to 2.32) and falls with injury (RR, 1.80; 95% CI, 1.12 to 2.98), adjusted for all other vision measures and potential confounding factors. Visual acuity, contrast sensitivity, and superior field loss were not associated with the rate of falls; topical beta-blocker use was also not associated with increased falls risk. Conclusions. Falls are common among older adults with glaucoma and occur more frequently in those with greater visual impairment, particularly in the inferior field region. This finding highlights the importance of the inferior visual field region in falls risk and assists in identifying older adults with glaucoma at risk of future falls, for whom potential interventions should be targeted.

Visual impairment and postural sway among older adults with glaucoma.

Purpose. To investigate the effect of visual impairment on postural sway among older adults with open-angle glaucoma. Methods. This study included 54 community-dwelling participants with open-angle glaucoma, aged 65 and older. Binocular visual field loss was estimated from merged monocular Humphrey Field Analyzer visual field results and retinal nerve fiber layer (RNFL) thickness was obtained from the Stratus Optical Coherence Tomographer. Postural sway was measured under four conditions: eyes open and closed, on a firm, and a foam surface. Data were collected for additional vision measures (visual acuity and contrast sensitivity), physical performance measures (self-reported physical activity levels and 6-min walk test), and demographic measures (age, gender, body mass index, and medical history). Multivariate linear regressions, adjusting for confounding factors, were performed to determine the association between visual loss and postural sway. Results. Participants with greater binocular visual field loss or thinner RNFL thickness showed increased postural sway, both on firm and foam surfaces, independent of age, gender, body mass index, and physical performance levels. These visual loss measures were significant predictors of postural sway, explaining almost 20% of its variance on the foam surface. Furthermore, participants with greater inferior hemifield visual field loss showed increased postural sway on the foam surface. Increasing glaucomatous visual impairment was accompanied by a steady decrease of the visual contribution to postural control. Conclusion. Among older adults with glaucoma, greater visual field loss or thinner RNFL thickness is associated with reduced postural stability. This postural instability may be a contributing factor in the increased risk of falls among older adults with glaucoma.

Postural stability and gait among older adults with age-related maculopathy

PURPOSE To assess the postural stability and gait characteristics of adults with age-related maculopathy (ARM) and to identify the visual factors associated with postural stability and gait in this clinical population. METHODS Participants included 80 individuals with a range of severity of ARM (mean age, 77.2 years). Binocular visual function measures included visual acuity, contrast sensitivity, and merged binocular visual fields. Postural stability was assessed on both a firm and a foam surface using center-of-pressure measures derived from a force platform. Forty three of the participants underwent a three-dimensional motion analysis to quantify gait characteristics, including walking velocity, proportion of time spent with both feet in contact with the ground (double-support time), stride length, and step width. RESULTS After adjustment for age, sex, self-reported physical function, and cataract severity, all the vision measures were significantly associated with postural stability on the foam surface, with contrast sensitivity being the strongest correlate. In the analysis of the gait measures, only contrast sensitivity was significantly associated with walking velocity, step width, or stride length, whereas contrast sensitivity and visual field loss were both significantly associated with double-support time. CONCLUSIONS Impaired contrast sensitivity was associated with postural instability, slower walking velocity, increased step width, and reduced stride length. Impairments in either contrast sensitivity or visual fields were associated with increased double-support time. This result suggests that loss of contrast sensitivity and visual fields in patients with ARM can lead to balance and mobility problems.

Mobility performance with retinitis pigmentosa

Purpose: Reduced mobility can have a serious impact on quality of life. Though previous studies have demonstrated that some vision measures relate to the mobility of subjects with simulated and true low vision, the relationship between residual vision and mobility is not clear. We investigated the relationship between clinical vision measures and mobility performance under different illumination levels for subjects with retinitis pigmentosa (RP).

Inferior visual field reductions are associated with poorer functional status among older adults with glaucoma

Citation information: Black AA, Wood JM & Lovie‐Kitchin JE. Inferior visual field reductions are associated with poorer functional status among older adults with glaucoma. Ophthalmic Physiol Opt 2011, 31, 283–291. doi: 10.1111/j.1475‐1313.2010.00811.x

Stepping accuracy and visuomotor control among older adults: effect of target contrast and refractive blur

Older adults have increased visual impairment, including refractive blur from presbyopic multifocal spectacle corrections, and are less able to extract visual information from the environment to plan and execute appropriate stepping actions; these factors may collectively contribute to their higher risk of falls. The aim of this study was to examine the effect of refractive blur and target visibility on the stepping accuracy and visuomotor stepping strategies of older adults during a precision stepping task.

Ocular disease and driving

As the driving population ages, the number of drivers with visual impairment resulting from ocular disease will increase given the age‐related prevalence of ocular disease. The increase in visual impairment in the driving population has a number of implications for driving outcomes. This review summarises current research regarding the impact of common ocular diseases on driving ability and safety, with particular focus on cataract, glaucoma, age‐related macular degeneration, hemianopia and diabetic retinopathy. The evidence considered includes self‐reported driving outcomes, driving performance (on‐road and simulator‐based) and various motor vehicle crash indices. Collectively, this review demonstrates that driving ability and safety are negatively affected by ocular disease; however, further research is needed in this area. Older drivers with ocular disease need to be aware of the negative consequences of their ocular condition and in the case where treatment options are available, encouraged to seek these earlier for optimum driving safety and quality of life benefits.As the driving population ages, the number of drivers with visual impairment resulting from ocular disease will increase given the age-related prevalence of ocular disease. The increase in visual impairment in the driving population has a number of implications for driving outcomes. This review summarises current research regarding the impact of common ocular diseases on driving ability and safety, with particular focus on cataract, glaucoma, age-related macular degeneration, hemianopia and diabetic retinopathy. The evidence considered includes self-reported driving outcomes, driving performance (on-road and simulator-based) and various motor vehicle crash indices. Collectively, this review demonstrates that driving ability and safety are negatively affected by ocular disease; however, further research is needed in this area. Older drivers with ocular disease need to be aware of the negative consequences of their ocular condition and in the case where treatment options are available, encouraged to seek these earlier for optimum driving safety and quality of life benefits.

Eye-Tracking as a Tool to Evaluate Functional Ability in Everyday Tasks in Glaucoma

To date, few studies have investigated the eye movement patterns of individuals with glaucoma while they undertake everyday tasks in real-world settings. While some of these studies have reported possible compensatory gaze patterns in those with glaucoma who demonstrated good task performance despite their visual field loss, little is known about the complex interaction between field loss and visual scanning strategies and the impact on task performance and, consequently, on quality of life. We review existing approaches that have quantified the effect of glaucomatous visual field defects on the ability to undertake everyday activities through the use of eye movement analysis. Furthermore, we discuss current developments in eye-tracking technology and the potential for combining eye-tracking with virtual reality and advanced analytical approaches. Recent technological developments suggest that systems based on eye-tracking have the potential to assist individuals with glaucomatous loss to maintain or even improve their performance on everyday tasks and hence enhance their long-term quality of life. We discuss novel approaches for studying the visual search behavior of individuals with glaucoma that have the potential to assist individuals with glaucoma, through the use of personalized programs that take into consideration the individual characteristics of their remaining visual field and visual search behavior.

Fear of falling in vision impairment

ABSTRACT Falls are the leading cause of injury-related morbidity and mortality among older adults. In addition to the resulting physical injury and potential disability after a fall, there are also important psychological consequences, including depression, anxiety, activity restriction, and fear of falling. Fear of falling affects 20 to 43% of community-dwelling older adults and is not limited to those who have previously experienced a fall. About half of older adults who experience fear of falling subsequently restrict their physical and everyday activities, which can lead to functional decline, depression, increased falls risk, and reduced quality of life. Although there is clear evidence that older adults with visual impairment have higher falls risk, only a limited number of studies have investigated fear of falling in older adults with visual impairment and the findings have been mixed. Recent studies suggest increased levels of fear of falling among older adults with various eye conditions, including glaucoma and age-related macular degeneration, whereas other studies have failed to find differences. Interventions, which are still in their infancy in the general population, are also largely unexplored in those with visual impairment. The major aims of this review were to provide an overview of the literature on fear of falling, its measurement, and risk factors among older populations, with specific focus on older adults with visual impairment, and to identify directions for future research in this area.