Abstract
Purpose :
Visual impairment (VI) is linked to fall risk in the elderly, and poor health in younger adults. We convened an interdisciplinary team of researchers with expertise in vision and mobility to focus our efforts on best practices in study of VI and physical mobility. A case control study compared balance and walking function between adults with juvenile onset VI (beginning before age 18), those with adult onset VI (beginning after age 18), and an age and gender matched control group without VI.
Methods :
We evaluated English speaking subjects over age 50, without dementia, vertigo, or postural hypotension, who could walk at least 100 feet independently. Subjects completed 4 vision tests: ETDRS visual acuity, Tangent Screen visual field, Mars contrast sensitivity, and Random Dot 2 stereoacuity; 3 mobility tests: gait analysis, Balance Error Scoring System (BESS) to assess static balance, 4 item Dynamic Gait Index (DGI) to evaluate variable gait function; 2 questionnaires: the Activity Balance Confidence (ABC) scale, the Independent Mobility Questionnaire (IMQ); and an interview about the history of their health and vision. Visual impairment was defined as having habitual vision worse than 20/70 in each eye or visual field loss of worse than 20 degrees.
Results :
To date, a total of 60 study participants had a mean age of 72 years, 33% were male. 29 subjects had VI, and of these 10 were juvenile onset, see table 1. There is a positive correlation between DGI score and age of onset of VI both in a t-test comparing both groups with VI (p=0.0016), as well as linear regression of age of onset of VI, see figure 1, indicating a weaker gait performance in individuals with earlier onset of VI. Many of the other factors we looked at were not significant.
Conclusions :
Analysis indicates that there is an association between years living with VI and reduced dynamic gait function. The DGI may have been more sensitive than other measures of motor performance. The group of subjects with juvenile onset VI scored worse on DGI, despite having no significant statistical difference in their balance confidence, static balance, gait velocity (results approach significance), or gait cadence. Our interdisciplinary team is exploring factors that could contribute to reduced mobility in populations of adults with VI.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.