Patients who scored abnormally on any one cognition test had a thinner retinal nerve fiber layer thickness compared with patients who did not score abnormally, according to study results presented at the Alzheimer’s Association International Conference.
“As ophthalmologists, we can play a role in monitoring systemic diseases. We already do in diseases like diabetes, or we offer screening to detect potential problems and allow general physicians to treat them systemically,” Fang Ko, MD, told Ocular Surgery News in an interview. “If it’s thought nerve fiber layer thinning is a link with [a patient’s] cognitive function and cognitive decline, then what they really need to do is talk to their primary care physician and possibly a neurologist to treat and slow the progression of this dementia.”
The study evaluated one eye of 32,038 patients of the U.K. BioBank. All patients underwent macular spectral-domain OCT, physical examinations and cognitive testing, and completed a questionnaire.
Cognitive measures included prospective memory, pairs matching, numeric and verbal reasoning, and reaction time.
In the prospective memory test, mean RNFL thickness was 53.3 µm in those who recalled correctly on the first attempt, 52.5 µm in those who recalled correctly on the second attempt and 51.9 µm in those who did not recall.
RNFL thinning was linked to poorer pairs matching, numeric and verbal reasoning, and reaction time on a univariate regression model (P < .001). Researchers observed that the effects were additive for each failed cognitive test.
After using multivariable regression modeling to adjust for age, sex, race, Townsend deprivation index, height, refraction and IOP, associations with RNFL thinning and poorer pairs matching, numeric and verbal reasoning, and reaction time remained significant.
“Our findings show a clear association between thinner macular RNFL and poor cognition in the study population,” Ko said. “This demonstrates the potential utility of the eye as a noninvasive measure of neuronal loss, which is linked to cognitive performance and provides a possible new biomarker for studies of neurodegeneration.” – by Nhu Te
Ko F, et al. Retinal nerve fiber layer thinning associated with poor cognitive function among a large cohort, UK BioBank. Presented at: Alzheimer’s Association International Conference; July 22-28, 2016; Toronto.
Disclosure: Ko reports she received funding from the National Institute for Health Research Biomedical Research Center at Moorfields Eye Hospital, a scholarship from University College of London and a travel grant from the Alzheimer’s Association International Conference.