Vision and hearing loss are likely to occur hand-in-hand in older people, research suggests.
Vision and hearing impairments in older people were linked
Australian scientists examined about 2,000 people with an average age of 70.
They found the volunteers with restricted eyesight were more likely to suffer hearing impairments and vice-versa.
Writing in the journal Archives of Ophthalmology, the researchers said the underlying causes for these sensory impairments may be the same.
Among the participants, all from the Blue Mountains region in New South Wales, Australia, 178 had a visual impairment, categorised as eyesight worse than 20/40.
And a further 56 had "best-corrected" visual impairment, meaning even when using glasses or contact lenses their eyesight was worse than 20/40.
Of this combined group, 206 people (88%) also had a hearing problem.
The researchers discovered that, for each line of the eye chart used by ophthalmologists that a volunteer could not see, there was an 18% (for the visually impaired) and 13% (for the best-corrected visually impaired) increase in the likelihood of hearing loss.
Conversely, those in the group that suffered hearing loss were 1.5 times more likely to have eyesight problems than those with good hearing.
The researchers also found that both those suffering age-related macular degeneration and cataracts were more likely to suffer hearing loss than those without these disorders.
The authors, from the University of Sydney and the National Acoustics Laboratories, Sydney, said the connection between vision and hearing could be explained by the fact that both are consequences of ageing.
They suggested common risk factors can predispose people to these sensory impairments.
They wrote: "Exposure to oxidative stress, cigarette smoking and atherosclerosis [hardening of the arteries] and its risk factors have been linked respectively to age-related macular degeneration, cataract and hearing loss.
Another common risk factor for cataract and visual and hearing impairments is diabetes.
"Further studies are needed to understand the relationship between visual and hearing impairments in older persons and to determine whether intervention to improve these impairments could delay biologic ageing."
Sue Brown, head of campaigns and public policy, Sense, a deaf-blind charity, said: "Dual sensory impairment or deaf-blindness is something which most people experience in their old age - Sense estimates there are currently two million people in the UK aged over 65 who are affected by a sight and hearing impairment.
"With an ageing population this number is set to increase making the issue of dual sensory loss even more relevant. The combined effect of a dual sensory loss causes difficulties with communication and mobility which are far greater than a single sensory loss."