September 14, 2022
2 minutes to read
Source / Disclosures
The authors do not report any relevant financial disclosures.
Retinal nerve fiber layer and ganglion cell layer thickness at 45 years of age have been associated with cognitive performance in childhood and adulthood, with a thinner retinal nerve fiber layer associated with a decrease in processing speed, according to the data.
“These findings suggest that the retina is a biological relationship with cognitive function,” Ashley Barrett-Young, Ph.D., of the Interdisciplinary Health and Development Research Unit at Dunedin at the University of Otago in New Zealand, and colleagues wrote in Gamma Ophthalmology. “It has been repeatedly observed that people with higher IQs tend to live longer and are healthier than those with lower IQs, but the mechanisms for this association are likely to be multispecies and complex.”
To examine whether the retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL) are associated with global cognitive performance and change in IQ at different life stages, Barrett Young and colleagues analyzed data from the multidisciplinary Dunedin Health and Development Study, which included 1,037 individuals born between April 1972 and March 1973 and were monitored until the age of 45 years.
Of the 938 participants seen up to the age of 45 years, 73 participants were excluded from the study due to complications of OCT scans (n = 63) and diseases affecting the retina (n = 10). The final data set included 865 individuals (50.2% men).
The results showed that a lower FSIQ at the age of 45 years (s < .001) with a thinner average thickness RNFL (s <.001), as well as the thinner nasal tetragon (s = .01) and the bottom quartile (s = .001). Lower FSIQ in childhood was associated with a mean RNFL thinner at 45 years of age (P < .001) and thinner RNFL in the nasal and lower quadrants, respectively (s = .008 and s <.001).
Thinner GCL thickness was also associated with lower FSIQ at age 45 years (s = .04), as was the thinner the upper temporal (s = .01), lowest (s = .02) and minimum time slices (s = .008). Inferior FSIQ of childhood was associated with thinner GCL thickness (P = .003), and thinner GCL in the temporal (P = .003).s = .001), superior (s = .01), superior to the nose (s = .03), lower nose (s = .01), lowest (s = .003) and minimum time plots (s = .001).
The researchers also reported that thinner RNFL thickness was associated with lower processing speed (s = .04).
Barrett-Young and colleagues conclude, “Our study used a unique life-cycle approach to show that RNFL, and to a lesser extent GCL, in middle age may reflect lifelong interindividual differences in global cognition.” “In addition, the RNFL may be particularly sensitive to changes in processing speed by middle age.”
They added, “RNFL thinning could be a useful biomarker in identifying those with early stages of cognitive decline before global cognitive decline becomes apparent. However, further longitudinal studies are needed to clarify whether retinal thinning is predictive of Alzheimer’s disease.” .