In the study, the relationship between impaired sight and impaired hearing was strongest among those under 70, suggesting that the two may be related to biological aging - meaning the "real age" of one's body based on genetic, environmental and lifestyle aging factors - rather than chronological age.

Dr. Ee-Munn Chia and colleagues at the University of Sydney also found that people with both hearing loss and vision loss reported worse quality of life than those with either type of sensory impairment alone.

The researchers looked at 2,000 men and women between 55 and 98 years of age. Roughly 9 percent of the men and women had vision loss and 40 percent had at least some hearing loss.

According to the investigators, visually impaired people were 60 percent more likely to have at least some moderate hearing loss, while hearing-impaired individuals were at a 50 percent increased risk of vision loss. The worse a person's vision loss, the greater his or her risk of hearing problems, and vice versa.

When the team looked specifically at the two most common causes of age-related vision impairment - cataracts and age-related macular degeneration (AMD) - they found that both were independently associated with hearing loss.

Vision and hearing loss share a number of common risk factors, including aging, cigarette smoking, atherosclerosis (hardening of the arteries) and diabetes, the researchers note.

Further studies are needed to understand the relationship between visual and hearing impairments, they concluded. Because more adults are living longer, the burden associated with age-related hearing and vision impairments is likely to increase.

Source: Archives of Ophthalmology, Oct. 2006