Abstract
Purpose :
Vision impairment may jeopardize the ability of older adults to maintain daily activity and also change when and how they perform activity. Using a prospective cohort of older glaucoma patients, we compared and contrasted activity fragmentation and activity timing across the spectrum of visual field (VF) damage.
Methods :
We categorized the degree of VF damage as follows: normal/mild (integrated VF [IVF] sensitivity >28 decibels [dB]), moderate (IVF sensitivity 23-28 dB), and severe (IVF sensitivity <23 dB). Participants wore accelerometers for one week to estimate the total active minutes per day and the number of activity bouts per day. Activity fragmentation was calculated as the reciprocal of average bout duration (higher fragmentation=more fragmented activity). We evaluated the associations of VF damage, measured in both categorical and continuous fashion, with activity fragmentation and activity time-of-day. We used multivariate linear mixed-effects model to detect VF damage differences across six different periods of the day (12a-4a, 4a-8a, 8a-12n, 12n-4p, 4p-8p, 8p-12a).
Results :
Participants with severe VF damage demonstrated a higher fragmentation index and less active time per day (p<0.05 for both), but maintained a similar number of bouts per day, compared to those with normal/mild VF damage (Table 1). Likewise, every five-unit (dB) decrement in IVF sensitivity was associated with an increase of fragmentation index and less active time per day (p<0.05 for both), but not the number of bouts per day. In time-of-day analyses, the severe VF damage group was less active compared to normal/mild VF group throughout daytime periods, i.e., 8a-12n, 12n-4p, 4p-8p (p<0.05 for all) (Figure 1). Similarly, for continuous analyses, every five-unit (dB) decrement in IVF sensitivity was associated with at least a 120 decrement in steps for the 8a-12n, 12n-4p, and 4p-8p time periods (p<0.05 for all).
Conclusions :
At worse levels of VF damage from glaucoma, physical activity is lower during typical waking hours, and spreads across more episodes of brief activity. Early transitioning into more fragmented activity and a more sedentary state at daytime may indicate a tailored physical activity regimen is needed to restore normal patterns of activity.
This is a 2020 ARVO Annual Meeting abstract.