Eye test may be early indicator of Alzheimer's, say scientists after linking brain disease to cataracts
Link could lead to new treatments for Alzheimer'sFinding indicates that dementia might originate outside of the brain and be connected to the body as a whole
08:02 GMT, 12 September 2012
Scientists have discovered a link between cataracts and Alzheimer’s that they hope will pave the way for new treatments for the brain disease.
The link could also mean a simple eye test might provide an early indicator that someone has Alzheimer's, according to a study.
The finding, by researchers at Boston University Schools of Medicine, indicates that dementia might originate outside of the brain and be connected to the body as a whole.
Opticians: A link between cataracts and Alzheimer's could mean a simple eye test might provide an early indicator that someone has the brain disease
A growing amount of evidence suggests cataracts and Alzheimer's – both associated with increasing age – may share common factors.
The discovery means diagnosing Alzheimer’s could be done earlier and suggests new treatment targets for the debilitating disease.
Scientists say there is a significant relationship between cortical cataracts – the most common form of the eye disease – and brain degeneration related to Alzheimer’s.
After looking at brain MRI findings a decade after an original eye exam, researchers found another link between cortical cataract formation and poorer results on cognitive tests given to patients.
They then performed a genome-wide association study on nearly 190,000 DNA sequence variations, focusing on a protein called delta-catenin.
The protein has previously been implicated in brain and eye development, but not directly in either cataracts or Alzheimer’s.
'This study gives hope that we are moving toward earlier diagnosis and new treatment targets for this debilitating disease'
After further tests however, the researchers discovered an increase in another protein that aggregates in Alzheimer brains and is thought to be central to the development of the disease.
The study also revealed increased deposits of delta-catenin in lens tissue of autopsy-confirmed Alzheimer’s cases.
Professor Lindsay Farrer, of Boston University Schools of Medicine, said: 'Though much work remains to be done, a link between cataracts and Alzheimer’s disease supports the idea of a systemic rather than brain-limited focus for processes leading to Alzheimer’s disease.
'This study gives hope that we are moving toward earlier diagnosis and new treatment targets for this debilitating disease.'
The research is published in the online journal PLoS ONE.