Partially sighted may be at higher risk of dementia

Older people with vision loss are significantly more likely to suffer mild cognitive impairment, which can be a precursor to dementia, according to a new study published in the journal Ageing Clinical and Experimental Research.

The research by Anglia Ruskin University (ARU) examined World Health Organisation data on more than 32,000 people and found that people with loss in both near and far vision were 1.7 times more likely to suffer from mild cognitive impairment.

People with impairment of their near vision were 1.3 times more likely to suffer from mild cognitive impairment than someone with no vision impairment.

However, people who reported only loss of their far vision did not appear to have an increased risk.

Dr. Lee Smith, Reader in Physical Activity and Public Health at ARU, said: "Our research shows for the first time that vision impairment increases the chances of having mild cognitive impairment. Although not everyone with mild cognitive impairment will go on to develop it, there is a likelihood of progression to dementia, which is one of the major causes of disability and dependency in the older population."

Co-author Shahina Pardhan, Director of the Vision and Eye Research Institute at ARU, said: "Research now needs to focus on whether intervention to improve quality of vision can reduce the risk of mild cognitive impairment, and ultimately dementia. More work needs to be done to examine any possible causation, and what the reasons might be behind it."

The researchers examined population data from China, India, Russia, South Africa, Ghana and Mexico from the WHO's Study on Global Ageing and Adult Health (SAGE). The overall prevalence of mild cognitive impairment was 15.3% in the study sample of 32,715 people, while around 44% of the total number of people surveyed had vision impairment.