Low visual acuity is associated with the decrease in postural sway.

Vision contributes to upright postural control by providing afferent feedback to the cerebellum. Vision is generally classified into central and peripheral vision, but little is known about the respective role of central and peripheral vision for postural control with different visual acuity levels. This study examined the influence of visual acuity and visual field conditions on upright posture. Eleven males (21.1 +/- 2.0 yrs) and 15 females (22.2 +/- 2.2 yrs) were classified into high (above 1.0 binocular vision) and low (below 0.3) visual acuity groups. Postural sway was measured for 1 min in each of three visual field conditions (central vision, full vision, and no vision). Participants were given only central visual information (central vision), central and peripheral visual information (full vision), or no visual information (no vision). The effect of central vision on postural sway was detected as a difference between no vision and central vision conditions, and the effect of peripheral vision was assessed as a difference between central vision and full vision conditions. The low visual acuity group decreased their sway amplitude in antero-posterior direction using central plus peripheral visual information, but the high visual-acuity group did not. The high frequency sway was significantly smaller in the low visual-acuity group than that in the high visual-acuity group under the no vision and central vision conditions. These findings suggest the necessity of considering participants' visual acuity in examining the role of the visual information from the central and peripheral visual fields.