2020 vision

Spotting Alzheimer’s disease (AD) before the first symptoms appear could soon be just an optical coherence tomography scan away, indicates new research presented at the Association for Research in Vision and Ophthalmology conference.

The international study discovered a link between the size of amyloid-beta protein aggregates found on a Heidelberg Spectralis OCT system and the pre-symptomatic build up of the protein in the brain, which signals the patients will develop the neurodegenerative disease.

Research lead author and Brown University neurology professor, Dr Peter Snyder, told OT that over the last 15 years scientists have been looking to the eye for clues about the Alzheimer’s-affected brain.

He explained: “The novel thing about our work is that we may be the first to explore [the retina in] preclinical AD. We are focusing – no pun intended – on the stage of disease prior to the onset of clinical symptoms.”

Being able to identify the pre-symptomatic condition is a key goal for medical researchers seeking to delay or even prevent the onset of AD, the world’s most common neurodegenerative disease.

Dr Snyder added: “Our sample has a mean age of 61, and none [of the subjects] yet meet diagnostic criteria for either mild cognitive impairment or AD – and they probably won’t for another five-plus years. However, many of them have enough beta-amyloid plaque deposits in the brain, [seen with] positron emission tomography imaging, and other significant risk factors to place them in a diagnostic category of ‘preclinical AD.’  The fact that we are finding retinal markers in this cohort is exciting to us.”

Dr Snyder emphasised that the goal was for an Alzheimer’s screening test to become part of a standard eye examination. But there is still several years of work left to do – the results of the just-published 63-person trial need to be replicated in a much   larger study and, after that, a quick screening methodology need to be developed.

An OCT system capable of detecting the amyloid-beta aggregates but also at a price affordable for most optometry practices is also key, Dr Snyder said.

“We are still several years off, at least, from wide deployment of a reliable screening diagnostic, but this is definitely what we hope to achieve,” he concluded.