Reduced motion detection may affect balance in older adults

Invest Ophthalmol Vis Sci. 2008;49(12):5257-5263.

Diminished ability to detect small movements or reduced visual fields may result in difficulties with balance in older adults, researchers have found. Their study is believed to be the first large-scale analysis of population-based data to gauge the extent to which visual function and motion detection affect balance.

Data were collected from the Salisbury Eye Evaluation project. The third round of the project included 1,505 patients ranging in age from 72 years to 92 years.

The ETDRS chart was used to assess visual acuity, which was converted to logMAR units. Contrast sensitivity, monocular visual fields and binocular visual fields were also tested. To measure motion detection thresholds, participants watched a short 1.5-second movie with an interactive component.

Participants with the worst motion detection threshold were less likely to complete a tandem stand (one foot behind the other) or a soleo stand (on one foot, eyes open, arms out). Subjects with the worst visual fields were less likely to complete a tandem stand. Poor contrast sensitivity was also associated with failed stands.

"In summary, we found that motion-detection threshold decrements are associated with poor balance," the study authors said. "Since poor balance is a risk factor for falling, we suggest that motion-detection threshold decrements may increase risk of falls and are worth further investigation."