In a study assessing the effects of visual factors on balance function, researchers recruited 43 teenagers and categorized them into three groups based on visual ability: blind ($n=12$), partially sighted ($n=9$), and normal vision ($n=22$). Participants underwent a one-leg stance test (under eyes-open or eyes-closed conditions) and a functional reach test (the normal vision group was tested under both eyes-open and eyes-closed conditions, while the other two groups were tested only under daily conditions).