A landmark New Zealand study uncovers a compelling connection: individuals with thinner retinal layers are more likely to underperform on cognitive tests. Published in JAMA Ophthalmology, these findings suggest retinal scans could help predict Alzheimer's risk earlier.
Alzheimer's disease and related dementias affect approximately 60 million people worldwide today, according to the Méderic Alzheimer Foundation. Projections estimate this figure will surpass 150 million by 2050. With no curative treatments available—and ongoing research exploring options like certain pharmaceuticals or vaccines in clinical trials—scientists are focused on detecting preclinical signs to enable earlier interventions.
A study published in JAMA Ophthalmology on February 10, 2022, by researchers at New Zealand's University of Otago examined the retina as a potential biomarker. They linked retinal thinning in midlife to diminished cognitive function, proposing that a simple eye exam might one day forecast Alzheimer's risk. Early identification could transform prevention strategies.
Drawing from the renowned Dunedin Multidisciplinary Health and Development Study, launched in New Zealand in the early 1970s with 1,000 participants, researchers analyzed a subgroup of 865 adults at age 45 in 2020. These individuals underwent detailed retinal imaging—optical coherence tomography (OCT), a non-invasive scan for early disease detection—and comprehensive neuropsychological assessments from childhood through adulthood.
The results were clear: those with thinner retinal layers showed poorer cognitive test results. Importantly, this thinning correlates with overall cognitive decline but isn't exclusively tied to neurodegenerative diseases—it may also reflect normal aging.
Prior research supports retinal thickness as a reliable indicator of brain health, aiding in cognitive decline monitoring and dementia diagnosis. The Otago team also highlights artificial intelligence's potential to enhance retinal analysis for precise Alzheimer's risk prediction.
