OBJECTIVES: To compare three-year longitudinal changes in gait across the spectrum of visual field (VF) damage among glaucoma patients in a prospective cohort study.

METHODS: VF damage was defined by averaging VF sensitivity across integrated VF (IVF) points, and categorizing average sensitivity as: normal/mild (IVF >28dB), moderate (IVF 23-28dB), and severe (IVF <23dB). Each participant walked on GAITRite Electronic Walkway back and forth twice at their normal pace each study year for three years. The outcomes were longitudinal changes in 7 gait assessments including: base support and its coefficient of variation (CV), stride length and its CV, stride velocity and its CV, and cadence. Linear mixed-effects models evaluated longitudinal change in gait outcomes stratified within each VF severity category, and across the range of IVF sensitivity. All gait metrics were converted to standardized z-score units .

RESULTS: Across three years of observation, stride length became shorter in persons with normal/mild, moderate, and severe damage (p<0.01 for all), while stride velocity and cadence slowed only amongst those with severe VF damage (β_{stride velocity} = -0.18 z-score unit, β_cadence= -0.15 z-score unit, p<0.01). Base of support, and CVs of base support, stride length, and stride velocity remained unchanged over the study period for all severity groups. When comparing longitudinal gait changes across the spectrum of IVF sensitivity, each 5-unit (dB) decrement was associated more rapid declines in stride velocity [-0.05 z-score unit/year; 95% CI, -0.09, -0.01] and cadence (-0.07 z-score unit/year; 95% CI: -0.10, -0.03), but not with declines in other gait metrics.

CONCLUSIONS: At worse levels of baseline VF damage, glaucoma patients demonstrate an exacerbated decline in walking speeds, indicating that mobility speeds decrease at a faster rate in visually impaired older adults as they age. Further work is needed to establish whether these longitudinal gait changes reflect effective adaptions to preserve safety.