The research showed that those with the thinnest RNFL were more likely to fail one of those tests.  Memory loss, difficulty carrying out routine tasks and other types of cognitive decline are often early symptoms of dementia.

Scientists believe that these simple eye tests could offer a relatively inexpensive and non-intrusive way of screening for dementia. 

However, they also believe such tests should not be carried out in isolation as there will be people with thinner retinas who do not go on to develop the disease or experience cognitive decline.