Eyes are the window to Alzheimer’s

They say the eyes are the window to the soul, but new research has shown they can reveal much more than our innermost thoughts and feelings. Researchers have discovered a future non-invasive retinal scan to detect the early signs of Alzheimer’s may be part of a routine GP or eye check-up for those over the age of 60 years.

The promising preliminary Australian research found changes in the brains of patients with Alzheimer’s were reflected in their eyes, specifically in the vessels of the retina.

If the findings are confirmed by a larger study which is now underway, it may allow Alzheimer’s to be diagnosed in advance before memory and thinking lapses develop.

Yogesan Kanagasingam, national research director of the Australian e-Health Research Centre (AEHRC) and acting head of health services at CSIRO, says although there is no cure at present, new medications to slow the progression of Alzheimer’s were being tested around the world.

“The main thing which will help immediately is patients can know that it is happening, and they and their families can prepare, organise carers and be ready,” Professor Kanagasingam says.

To analyse the retinal blood vessels, GPs would only require an eye scanner – already used by most ophthalmologists and optometrists – and a special computer software system developed by the CSIRO.

“Our plan is for people to go to the GP or primary care provider who can carry out the imaging,” Professor Kanagasingam says. “But the fundus cameras are pretty expensive at the moment,” he admits.

In the preliminary study, there were 110 healthy subjects, 13 subjects with Alzheimer’s and another 13 with mild cognitive impairment or pre-Alzheimer’s.

The researchers compared brain scans with retinal scans; which showed the widths of certain blood vessels and the amount of difference matched the amount of plaque seen in the brain scans.

“We see a very good correlation between the retinal vessels’ calibre and the beta-amyloid loading in the brain,” Professor Kanagasingam says.

“The vessels are all connected to the brain so whatever changes there are in the brain, affect the eye as well. Basically whatever happens in the body actually happens in the eyes,” he claims.

The larger study, the Australian Imaging, Biomarker and Lifestyle (AIBL) Flagship Study of Ageing, is being conducted by CSIRO and its partners, and will involve about 1,000 patients in Perth and Melbourne.

A US study of the lens of the eye in Alzheimer’s patients has suggested beta-amyloid plaques may be laid down in the eye.

“We are not going down that path but if we come across that during our research, that is great,” Professor Kanagasingam says.

At present, the only way to detect Alzheimer’s is through brain imaging, which Professor Kanagasingam says is an “invasive process”.

“So, if you could image the eye non-invasively it would be a huge plus and make things very easy, with no radiation to the body,” he says.