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by Satina Richardson

UAB School of Optometry vision scientists are participating in research to evaluate how changes in the retina might play a role in diagnosing Alzheimer’s disease. Their findings could lead to non-invasive, low-cost tests and the early diagnosis of the disease, which progresses for decades before symptoms of dementia emerge.

Alzheimer’s disease, a progressive neurodegenerative disease affecting approximately 6.7 million Americans aged 65 and older, is the most common cause of dementia in the elderly. By 2060, the affected population is projected to reach 13.8 million unless effective interventions or treatments become available.

In 2023, Edmund Arthur, OD, PhD, was awarded a $408,375 two-year pilot grant from the National Institute on Aging to study eye doctors’ role in diagnosing Alzheimer’s disease by examining the retina.

“While rapid advances in blood-based biomarkers will likely become part of the normal clinical diagnostic pathway within the next few years, there is still the need for other non-invasive biomarkers,” he said.

He is collaborating with Erik Roberson, MD, PhD, neurologist and director of UAB’s Alzheimer’s Disease Research Center. The UAB Brain Aging and Memory Clinic provides a team-based approach to evaluating, diagnosing, and treating people experiencing age-related cognitive changes and supporting their families and caregivers.

“Our population is aging, so more and more people are living longer and experiencing age-related cognitive changes,” Roberson said. “Combined with a shortage in Alabama of neurologists in general, and those trained in dementia in particular, along with the emergence of new disease-modifying therapies, the demand for appointments in our UAB Brain Aging and Memory Clinic is tremendous.”

Roberson provides the participants and their blood-based biomarkers for the study, while Arthur performs the retinal imaging component of their research.

One of Arthur’s goals is to develop a multimodal model incorporating two novel retinal biomarkers—the retinal peripheral capillary free zones and retinal putative gliosis—and blood-based biomarkers to screen for early Alzheimer’s disease.

“The retina allows for a non-invasive look at the central nervous system, making it an ideal target for the development of early Alzheimer’s disease biomarkers,” Arthur said. “The idea is that an optometrist could order blood tests as additional confirmation after seeing early signs of Alzheimer’s disease in the retina.”

Research participants undergo a series of non-invasive tests as part of the study: visual function tests, including field of vision and sensitivity to contrast assessments, as well as multimodal retinal imaging assessment, including Spectral Domain Optical Coherence Tomography (SD-OCT), OCT Angiography, and Blue Autofluorescence imaging.

These tests are more accessible, more affordable, and less invasive than the positron emission tomography and cerebrospinal fluid analysis evaluation methods, which currently have the greatest utility.

Arthur shared that characterization, quantification, and validation of these non-invasive retinal biomarkers for early Alzheimer’s disease detection will provide low-cost screening tools for Alzheimer’s disease prevention trials, expedite enrollment and randomization, and could potentially serve as a tool for monitoring the efficacy of secondary prevention therapeutics.

Alzheimer’s disease is currently a very hot topic and potentially an area of research growth and strength for UABSO. Tim Kraft, PhD, first researched the topic in 2014 and, with renewed interest, has a grant submission to the NIH to measure retinal function and anatomy in a mouse model of Alzheimer’s disease. His research will also perform parallel tests on human subjects who are young, old and in the beginning stages of dementia.

Growing the tools to allow for earlier diagnosis will greatly benefit patients. “Our work will facilitate large-scale screening of older adults by point-of-care clinicians, including optometrists, and referral of at-risk individuals to neurologists and neuropsychologists for detailed cognitive health/biomarker assessment,” Arthur added. “The impact could lessen the disease’s overall burden on our society, patients and caregivers alike.”