Eye scan detects Alzheimer’s in mice before any symptoms have appeared

New eye-scanning technology can detect Alzheimer’s disease before symptoms appear, according to a study published in the journal Investigative Ophthalmology and Visual Science.

Research until now has been carried out on mice, but human clinical trials of ‘hyperspectral endoscopy’ — in which observations of the brain are made through the eye — are scheduled to begin this month.

Studies have shown that when the first symptoms of the disease appear (such as amyloidopathy and cognitive impairment), other signs that are more difficult to detect have been present for decades. Currently it is only possible to absolutely confirm Alzheimer’s disease postmortem.

But researchers found that, in mice at least, the gathering of amyloid plaque was evident in the way light was reflected by the retina.

The study’s lead author, Robert Vince, said: ‘Early detection of Alzheimer’s is critical for two reasons. First, effective treatments need to be administered well before patients show actual neurological signs. Second, since there are no available early detection techniques, drugs currently cannot be tested to determine if they are effective against early Alzheimer’s disease. An early diagnostic tool like ours could help the development of drugs as well.’

Instant analysis
Early diagnosis and effective treatment of Alzheimer’s disease remains one of the holy grails of medicine and huge amounts of study and money are being put into ways of reducing its impact on future ageing populations.

One of the dream scenarios here is a diagnostic test that shows the presence of the disease before any obvious symptoms of cognitive decline develop. One potential way of doing this is to look at the back of the eye (the retina) which, unlike the brain, is readily accessible to being seen.

Although this study has yet to be replicated in humans, it showed that changes in the retina of mice with Alzheimer’s appeared before neurological signs were observed. If this can be extrapolated and reproduced in humans — and clinical trials are to be started soon — then this has the potential to be an early diagnostic test for Alzheimer’s disease.

As always, the potential is massive and the timescale long, but if doctors were able to diagnose Alzheimer’s at the earliest possible opportunity then any new treatments available to treat or slow its progress would be an exciting prospect. Time will tell, however.
RH
Research score: 4/5