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Retinal findings facilitate research in neurodegenerative disease
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CHICAGO – “There is mounting evidence that the retina is an extension of the brain, and it also manifests morphological changes in neurodegenerative diseases,” Christopher Hudson, PhD, MCOptom, FAAO, said here at the American Academy of Optometry.
Hudson discussed his research as part of the plenary session, which was co-sponsored by Primary Care Optometry News.
“The retina is an appealing target for noninvasive optical imaging and surrogate quantification of these diseases,” Hudson said. “Spectral domain optical coherence tomography may ultimately have a role in diagnosis and monitoring.”
Hudson outlined the ongoing Ontario Neurodegenerative Disease Research Initiative (ONDRI), a multicenter trial designed to study dementia and improve the diagnosis and treatment of neurodegenerative diseases including Alzheimer’s, Parkinson’s, amyotrophic lateral sclerosis (Lou Gehrig’s disease), frontotemporal lobar degeneration and vascular cognitive impairment resulting from stroke, according to the ONDRI website.
“The thing that ties these diseases together is dementia,” said Hudson, who has Parkinson’s disease. “It is the most difficult and expensive manifestation of neurodegenerative disease.”
Hudson said the ONDRI seeks to identify “common and unique early indicators of risk factors.”
The ONDRI comprises more than 600 participants, 50 core investigators and 20 clinical sites.
“Results will translate into new diagnostic methods that will help detect diseases earlier, improve clinical practice that puts patients first, develop new and effective treatments to slow progression or even prevent diseases,” Hudson said.
Optic nerve degeneration and loss of retinal ganglion cells was demonstrated histologically in Alzheimer’s disease patients about 30 years ago, Hudson told attendees.
“Retinal nerve fiber layer thinning in vascular cognitive impairment was intermediate to that in Alzheimer’s disease,” he said. “That thinning relates to the severity of disease.
“With Parkinson’s, there’s a similar story,” Hudson continued, “although the signal effect seems to be larger in Alzheimer’s.”
Inner nuclear layer thickness is greater in patients with Parkinson’s vs. controls, he said, and there is evidence of an increase in volume in the outer plexiform layer.
“That’s possibly reflecting some inflammatory process, or it could be artifact,” Hudson said.
“Alpha-synuclein is a hot topic in current literature,” he said. “There is no direct evidence that the thickening was a direct result of the alpha-synuclein. This highlights the need for analysis of layers of the retina, not just general thickness.”
Hudson concluded: “Human disease does not come in perfectly defined packages. We need to deal with these concomitant pathologies in order for the study to be successful and, more importantly, for the techniques to be useful and usable on a clinical basis in the future.” – by Nancy Hemphill, ELS, FAAO
Reference:
Hudson C. How to use OCT to diagnose and monitor neuro-ophthalmic diseases: Multiple sclerosis, diseases that mimic MS and maybe Alzheimer’s. Presented at American Academy of Optometry meeting; Chicago; Oct. 12, 2017.
Disclosure: Hudson reported no relevant financial disclosures.