The findings, published in the American Journal of Epidemiology showed that the Elderly adults with poor vision, particularly untreated vision problems, had a higher risk of developing dementia.

Among the 625 older Americans with initially normal cognition, those who had poor vision were found more likely to develop dementia.

During the study of 168 participants who developed Alzheimer's disease, less than 10% had rated their vision as "excellent" at the start of the study, compared with almost 31% of participants who maintained normal brain function.

When the researchers looked at the effects of treatment, they found that the highest odds of dementia were among people with poor vision left untreated. The risk was lower when they received some form of eye care.

Dr. Mary A. M. Rogers, a research Assistant Professor of Internal Medicine at the University of Michigan in Ann Arbor said that the current studies showed vision problems precede a dementia diagnosis.

Walking, reading, doing crosswords or socializing, decrease the risk of dementia in older adults.