Effect of Prism Base Directions on Posture Stabilization

Abstract

The eye’s position was changed by adding 1△ (prism diopter) prism according to a various direction of base and we investigated the effect of prism base directions on posture stabilization. The subjects were 8 healthy volunteers and the sway of the center of gravity was measured with stabilometer UM-BAR II (UNIMEC) during 1 min. Visual acuity of each eye was perfectly corrected by glasses and it was compared with the condition used 1Δ prism at a time when it was changed from Nasal to Infra–Nasal (total 360 degrees) per 45 degrees only the dominant eye. In the results of position vector, anterior sway increased at base Superior and posterior sway increased at base Infra–Temporal and Inferior in particular (p<0.05). These results suggest that prism effect of vertical degree influenced the posture stabilization and that this change relies upon fusional area and phoria adaptation.