Eye scan reveals Alzheimer’s years before symptoms appear

For decades, the only way to officially diagnose Alzheimer’s disease was by analysing a patient’s brain during a postmortem. More recently, physicians have been able to use positron emission tomography scans of the brains of living people to provide evidence of the disease – but the technology is expensive and invasive, requiring the patient to be injected with radioactive tracers.

Now researchers from Cedars-Sinai Medical Centre in the US have discovered that Alzheimer’s disease affects the retina – the back of the eye – similarly to the way it affects the brain. The study also revealed that a noninvasive eye scan could detect key signs of the disease years before patients experience symptoms.

Using a high-definition eye scan developed especially for the study, researchers detected the crucial warning signs of Alzheimer’s disease: deposits of toxic proteins called amyloid-beta.

The researchers behind the work say it represents a major advancement toward identifying people at high risk for the debilitating condition years sooner.

The study’s senior lead author, Maya Koronyo-Hamaoui, said: The findings suggest that the retina may serve as a reliable source for Alzheimer’s disease diagnosis. One of the major advantages of analyzing the retina is the repeatability, which allows us to monitor patients and potentially the progression of their disease.’

Another finding from the new study, which has been published in the Journal of Clinical Investigation, was the discovery of amyloid plaques in previously overlooked peripheral regions of the retina.

Keith Black, the study’s co-lead author, said the findings offer hope for early detection when intervention could be most effective: ‘Our hope is that eventually the investigational eye scan will be used as a screening device to detect the disease early enough to intervene and change the course of the disorder with medications and lifestyle changes.’