The effect of binocular peripheral vision blocks (partial and complete), on balance in healthy young Indian adults: An experimental study

Abstract

QUESTION: How does the dynamic balance during functional tasks change with partial and complete peripheral vision blocks (CPVBs) as compared to full vision and no vision? DESIGN: Randomized, within-participant experimental study. PARTICIPANTS: Sixty young Indian adults (18–39 years) with normal 6/6 vision. METHODS: Dynamic balance was tested and compared in functional activities on a long force plate (Neurocom Smart Version 8.6 Balance Master) with eyes open (EO), partial peripheral vision blocks (PPVB), Complete peripheral vision blocks (CPVB), and eyes closed (EC). OUTCOME MEASURES: Center of gravity (COG) sway velocity in Sit to Stand (STS); Movement Time in Step up and Over (SUO); Step length, Step width and Speed in Walk Across (WA). RESULTS: (1) Walk across: A significant linear trend was observed in the reduction of step length when the visual alterations were intensified, and there was no significant difference between EO versus PPVB (d = 0.06, 95% confidence interval [CI] - 1.78–3.41). With CPVB versus EC (d = 0.35), walking speed showed a considerable decrease. (2) Step quick turn: No significant difference between (a) turn time (EC vs. CPVB: d = 0.28; EO vs. PPVB: d = 0.13) and (b) turn sway (EC vs. CPVB: d = 0.24; EO vs. PPVB: d = 0.09). (3) Sit to stand: The sway velocity was least with CPVB with a nonsignificant linear trend (P = 0.71). (4) Step up and over: A clinically significant difference was obtained in EO versus EC, EC versus CPVB and EC versus PPVB but not with EO versus PPVB, EO-CPVB and PPVB versus CPVB. CONCLUSION: These results reveal that in the normal young population, balance performance deteriorates as the availability of peripheral vision decreases, to the extent that in some functional activities, dynamic balance with CPVB is similar to the EC condition.