Body balance under ametropic conditions induced by spherical lenses in an upright position.
[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.
Department of Optometry, Kangwon National University, Republic of Korea.
Sang-Yeob
SY
Kim
Department of Optometry, Kangwon National University, Republic of Korea.
Byeong-Yeon
BY
Moon
Department of Optometry, Kangwon National University, Republic of Korea.
Hyun Gug
HG
Cho
Ametropia; Body balance; Fall risk index