Influence of changes in visual acuity under various visual field conditions on the spectral characteristics of center of pressure sway.
OBJECTIVE
This study aimed to examine the influence of visual information (visual acuity and visual field conditions) on the center of pressure (COP) sway spectrum.


METHODS
The subjects were 17 healthy young adults (7 males and 10 females), whose naked eye binocular visual acuity was under 0.2 (mean naked eye visual acuity: 0.1+/-0.1; mean corrected vision: 1.3+/-0.3). They participated in COP measurements under 2 kinds of visual acuity conditions (naked eye and vision correction conditions) and 3 visual field conditions (no vision: no visual information; central vision: only central visual field information; and full vision: full visual information). Spectral characteristics of COP sway of anterior/posterior (Y) and medial/lateral (X) directions were assessed using mean power frequency and frequency of maximal power (FMP).


RESULTS
The Friedman test and Scheffe's pairwise comparison test showed that the FMP of posterior-anterior COP sway was higher in no vision and central vision than in the full vision condition in the vision correction condition. In the naked eye condition, there was no significant difference in any parameter between visual field conditions.


CONCLUSIONS
In summary, although people with low visual acuity are little affected by changes of visual fields with naked eyes, with temporal vision correction they show differences in X and Y sway spectrum characteristics between visual field conditions. During vision correction, the wider their visual fields, the more low frequency sway they have. Even a temporal improvement of visual acuity may contribute to stability in an upright standing posture.
Uchiyama
M
M
Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Japan. masanobu@ed.kanazawa-u.ac.jp
Demura
S
S
D000328:Adult; D005260:Female; D005583:Fourier Analysis; D006801:Humans; D008297:Male; D004856:Postural Balance / Q000502:physiology*; D011601:Psychophysics; D012815:Signal Processing, Computer-Assisted; D018709:Statistics, Nonparametric; D014787:Vision Tests; D014792:Visual Acuity / Q000502:physiology*; D014794:Visual Fields