Abstract
Purpose:
To assess the adaptive gait of patients with peripheral visual field loss due to glaucoma when crossing obstacles of varying heights, in two different light conditions.
Methods:
Three-dimensional kinematic data were collected from twenty-five glaucoma (73.2 ± 8.3 years) and twenty-three normally sighted control participants (71.6 ± 6.9 years). Participants walked up to and stepped over either a low (5 cm) or high (10 cm) floor based obstacle in both bright (800 lx) and dim (8 lx) lighting conditions. Movement patterns of both the lead and trail limb were analysed. Peripheral visual field loss among the glaucoma group was confirmed using Humphrey 30-2 SITA standard tests.
Results:
Statistically significant between-group differences were observed in vertical foot clearance for the high obstacle, in bright light condition (p=0.022) and also for the low obstacle in dim light condition (p=0.022); this difference approached statistical significance for the low obstacle, in bright light condition (p=0.056). Across conditions, glaucoma patients lifted their lead foot 10% higher over the obstacle compared to normally sighted controls. Glaucoma patients also lifted the toe of their trail limb 12% higher than the normally sighted controls and the velocity with which their lead and trail foot crossed the obstacle was 5% slower than the visual normals; however these were not statistically significant. Within the key kinematic variables analysed there was considerable overlap between the distributions of the two groups. This overlap was likely due to the range in severity and location of peripheral visual field loss in the glaucoma group.
Conclusions:
In comparison to normally sighted controls, glaucoma patients exhibit moderate adaptations in gait when performing an obstacle crossing task. These subtle differences may indicate that glaucoma patients adopt a cautious approach to mobility tasks that present a high risk of falling.
Keywords: 408 adaptation: motion •
758 visual fields •
753 vision and action