Parts of our retina have previously been proposed as biomarkers for Alzheimer’s, but researchers from Otago University’s Dunedin Multidisciplinary Health and Development Research Unit have been investigating the retina’s potential to indicate cognitive change earlier in life.
The study, published in JAMA Ophthalmology, analyzed data from 865 Dunedin Study participants looking specifically at the retinal nerve fibre layer (RNFL) and ganglion cell layer (GCL) at age 45.
The researchers found that thicker RNFL and GCL in middle age was associated with better cognitive performance in childhood and adulthood. Thinner RNFL was also linked to a greater decline in processing speed (the speed in which a person can understand and react to the information they receive) from childhood to adulthood.
“These findings suggest that RNFL could be an indicator of overall brain health. This highlights the potential for optical scans to aid in the diagnosis of cognitive decline, “says study lead Ashleigh Barrett-Young, PhD, Postdoctoral Fellow at Otago University in Dunedin, New Zealand. “Given we haven’t been able to treat advanced Alzheimer’s, and that the global prevalence of the disease is increasing, being able to identify people in the preclinical stage, when we may still have the chance to intervene, is really important,” she says.
Further studies are required to determine if retinal thinning predicts Alzheimer’s, or just the normal cognitive decline of old age, but the researchers have hope.
“In the future, these findings could result in AI being used to take a typical optical coherence tomography scan, done at an optometrist, and combine it with other health data to determine your likely risk for developing Alzheimer’s,” Barrett-Young said.
