Glaucoma-related changes in gaze behavior affect mobility but are modifiable

Abstract

Visual field loss associated with glaucoma affects mobility, resulting in slower walking, increased obstacle collisions, and more falls. Glaucoma-related visual loss may disrupt appropriate gaze behavior and gaze-foot coupling, which are necessary for safe route selection and foot placement. We first tested the hypothesis that gaze behavior is different between older adults with glaucoma (n = 10) and normal-sighted controls (n = 10), and that this affects mobility. Subjects performed a precision walking task where they stepped to the center of four irregularly spaced targets under three conditions: targets only, dual search, and dual count. In the targets only condition, subjects only performed the precision walking task. In the dual search condition, subjects had to find and recall the location of one of four shapes along the perimeter of the walkway while performing the precision walking task. In the dual count condition, subjects counted backwards while performing the precision walking task to simulate a conversation. We recorded gaze behavior with a head-mounted mobile eye tracker and foot placement with a motion capture system. In all conditions, the glaucoma group shifted gaze off targets sooner relative to when their heel contacted them; this is associated with a high risk of falling in older adults (Chapman and Hollands, 2006). They also had greater foot-placement error than controls. Subsequently, we developed a gaze training intervention to modify gaze behavior. We taught (2, 1-hr sessions) older adults with glaucoma (n = 2) appropriate scanning and task-specific gaze strategies. To assess its effectiveness, subjects performed the precision walking task before and one week after training. After training, subjects shifted gaze off targets later relative to stepping on them and decreased foot-placement error in all conditions. These preliminary results suggest that gaze is modifiable in older adults with glaucoma, and that gaze training may improve mobility.

Meeting abstract presented at VSS 2017