[Purpose] To investigate the changes in body balance under ametropic conditions induced
by spherical lenses in an upright position. [Subjects and Methods] Twenty subjects (10
males, 10 females) of average age 23.4±2.70 years participated and they were fully
corrected by subjective refraction. To induce ametropic conditions (binocular myopia and
hyperopia), lenses of ±0.50 D, ±1.00 D, ±1.50 D, ±2.00 D, ±3.00 D, ±4.00 D and ±5.00 D
were used. General stability (ST), fall risk index (FI), and sway path (SP) were analyzed
through changes in synchronization of left/right and toe/heel, as measured by the
biofeedback system, TETRAX. Measurement was performed for 32 seconds for each condition.
[Results] ST increased significantly from +0.50 D-induced myopia and from −1.00 D-induced
hyperopia as compared with corrected emmetropia. FI increased significantly from +4.00
D-induced myopia and from −1.50 D-induced hyperopia as compared with corrected emmetropia.
In SP, which means a change of body balance, toe/heel was significantly greater than
left/right in all ametropic conditions. SP of right/left synchronization was not affected
by the side of the dominant eye. [Conclusion] An uncorrected hyperope may cause subjects
to have a higher risk of falling than an uncorrected myope. Therefore, clinical
specialists should consider the refractive condition, especially hyperopia, when analyzing
body balance.