Are there indicators of Alzheimer’s disease in the eye?: New computational imaging and analysis algorithms

Michael Smith Foundation for Health Research/The Pacific Alzheimer Research Foundation Post-Doctoral Fellowship Award

 

Alzheimer’s disease (AD) is progressive degeneration of the brain that results in loss of memory and cognitive abilities. The prevalence of the disease presents a daunting challenge — as of 2015, 46.8 million people in the world live with AD, with the number expected to double by 2035. In Canada, 14.9 percent of those 65 and older have the disease. The global health-care cost for dementia has exceeded 1 percent of the global gross domestic product (GDP).

 

AD significantly affects the quality of life for the patients and caregivers, and this makes early detection critical. However, the brain imaging required for the diagnosis is costly, and AD is often discovered only after it has progressed considerably.

 

The overarching theme of this project is finding the connection between the eye and AD, by investigating it for potential biomarkers of the disease. The eye is an extension of the brain, with the optic nerve forming a direct physical connection between the retina and the brain’s visual cortex. Recent advances in ophthalmic imaging techniques, such as optical coherence tomography (OCT), provides high-resolution 3D visualization of the inner structures of the eye, including the retina, nerve fibres, and blood vessels, in a noninvasive manner. OCT and other imaging techniques give us a comprehensive picture of the eye’s health and function.

 

We will develop image processing and analysis tools to examine chemical biomarkers, structural degradation, and functional loss in the eye that may be associated with AD. The project will potentially lead to discovery of novel AD biomarkers in the eye, and a cost-effective and accessible diagnostic tool for early detection of AD.

 

End of Award Update

Source: CLEAR Foundation

 

What did we learn?

We know that amyloid beta, a hallmark of Alzheimer’s disease, is present not only in the brain but also in the retina of the patients, and its deposition can vary by location and comorbidity such as cerebral amyloid atrophy.

 

Why is this knowledge important?

Retina can be readily imaged in high detail, and it contains rich information about the person’s neuronal health. Retinal imaging has potential as an early and accessible screening tool for neurodegenerative diseases. Studying the mechanisms of Alzheimer’s disease pathology in the retina also gives us insight into those in the brain.

 

What are the next steps?

Professor Joanne A. Matsubara’s group at the University of British Columbia and I are continuing to collaborate to study retinal biomarkers of Alzheimer’s disease. We are currently looking into how amyloid beta affects glial cells and blood vessels in the retina.

 

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