[sweetwater]

I may not have been very clear. It's an inner ear and therefore balance issue that forces one to rely on visual clues to maintain balance, and that forces knees to constantly make adjustments, and that excess wear and tear on the knees causes problems. One can hear fine and have inner ear problems. It's just fairly common to have sore knees when the balance is off, and that test (standing with eyes closed) deprives the brain of visual cues making the problem easier to pinpoint.