Visual impairment and postural sway among older adults with glaucoma

Purpose. To investigate the effect of visual impairment on postural sway among older adults with open-angle glaucoma. Methods. This study included 54 community-dwelling participants with open-angle glaucoma, aged 65 and older. Binocular visual field loss was estimated from merged monocular Humphrey Field Analyzer visual field results and retinal nerve fiber layer (RNFL) thickness was obtained from the Stratus Optical Coherence Tomographer. Postural sway was measured under four conditions: eyes open and closed, on a firm, and a foam surface. Data were collected for additional vision measures (visual acuity and contrast sensitivity), physical performance measures (self-reported physical activity levels and 6-min walk test), and demographic measures (age, gender, body mass index, and medical history). Multivariate linear regressions, adjusting for confounding factors, were performed to determine the association between visual loss and postural sway. Results. Participants with greater binocular visual field loss or thinner RNFL thickness showed increased postural sway, both on firm and foam surfaces, independent of age, gender, body mass index, and physical performance levels. These visual loss measures were significant predictors of postural sway, explaining almost 20% of its variance on the foam surface. Furthermore, participants with greater inferior hemifield visual field loss showed increased postural sway on the foam surface. increasing glaucomatous visual impairment was accompanied by a steady decrease of the visual contribution to postural control. Conclusion. Among older adults with glaucoma, greater visual field loss or thinner RNFL thickness is associated with reduced postural stability. This postural instability may be a contributing factor in the increased risk of falls among older adults with glaucoma.