Influences of monocular and binocular vision on postural stability.

To compare the influences of monocular vision versus binocular vision on postural control, twenty-seven otherwise healthy adults, aged from 19 to 38 years, with corrected visual acuity of better than or equal to 20/20, were recruited. Body sway for standing 30 seconds on a force platform in 3 conditions was recorded for each participant: one with both eyes open (BEO), one with left eye open (LEO) and the other with both eyes closed (BEC). Postural stability was subsequently evaluated by measuring the total track length (TL) and surface area (SA) of center of pressure of body sway. The results show that the values of TL and SA of BEC were significantly greater than those of LEO and BEO. Moreover, the values of TL and SA of BEO were significantly smaller than those of LEO (p < 0.05, one-way repeated measures ANOVA and post hoc of Fisher's LSD procedure). The Romberg coefficient of LEO was also significantly greater than that of BEO (p < 0.05, paired sample t-test). We concluded that optimal binocular vision provides more information for keeping balance than monocular vision according to the results revealed in our study. Assessment of visual acuity is recommended before doing a posturographic test in the clinical setting. However, the long-term impact of blindness on controlling posture is uncertain and needs further investigation.