A simple eye test may be an early indicator of Alzheimer's disease, say scientists. This follows previous findings that a toxic protein, that builds up in the brains of dementia patients causing confusion and memory loss also accumulates in the eyes, the Daily Express reported.
Now they have found that not only are dementia and cataracts linked, but that Alzheimer's may be triggered from outside the brain.
The revolutionary findings by the Boston University Schools of Medicine and Public Health in Massachusetts has paved the way for an opticians' eye test to detect the degenerative disease early.
For the findings, the researchers looked at brain scans a decade on from original eye examinations.
They concluded that there was a link between cortical cataracts - the most common form - and Alzheimer's-related measures of brain degeneration.
The researchers then looked at nearly 190,000 DNA sequence variations.
The protein deltacatenin appeared to be particularly important and further research found that there was increased deposits of it in lens tissue in people who had Alzheimer's - but not from those who didn't.
This suggested that both diseases could have the same origin.
"This study gives hope we are moving toward earlier diagnosis and new treatment targets for this debilitating disease," Professor Lindsay Farrer, from the Boston team, said.
"This study highlights some interesting avenues for further investigation." Jessica Smith, from the Alzheimer's Society, said.
The findings have been published in the online journal PLoS ONE.