Reading cognition from the eyes—association of retinal nerve fiber layer thickness with cognitive performance in a population-based study

Abstract

With the eye as window to the brain, non-invasive fast screening of retinal nerve fiber layer thickness poses the opportunity for early detection of cognitive decline leading to dementia. Our objective is to determine whether performance in various neurocognitive tests has an association with itemized retinal nerve fiber layer thickness. Detailed investigation of associations factored in sex and eye-side. The large population-based LIFE-Adult study (Leipzig Research Centre for Civilization Diseases) was conducted at Leipzig University, Germany from 2011 to 2014. Randomly selected participants (N = 10,000) were drawn from population registry in an age- and gender-stratified manner, focusing on 40–80 years. Cognitive function was examined with the CERAD-NP Plus test-battery (Consortium to Establish a Registry for Alzheimer's Disease), Stroop-Test, Reading the Mind in the Eyes-Test, Multiple-Choice Vocabulary Intelligence Test. Circumpapillary retinal nerve fiber layer thickness was measured with Optical Coherence Tomography. Subjects with reliable measurements (≥50 B-scan repetitions, signal-to-noise-ratio ≥20 dB, ≤5% missing A-scans) and without clinical eye pathology (sample A) and additional exclusion due to conditions of the central nervous system (sample B) were evaluated. The relationship between cognitive function and retinal nerve fiber layer thickness was investigated for six segments: temporal, temporal-superior, temporal-inferior, nasal, nasal-superior, nasal-inferior. For comparison with other studies, global mean is given. Brain-side projection analysis links results to corresponding brain hemisphere. We analyzed 11,124 eyes of 6,471 subjects (55.5 years of age [19.1–79.8 years], 46.9% male). Low cognitive performance was predominantly associated with thinner retinal nerve fiber layer thickness. Correlation analysis indicated emphasis on global and temporally located effects. Multivariable regression analysis with adjustments (age, sex, scan radius) presented individual results for each test, differentiating between sex and eye-side. For instance verbal fluency tests and Trail-Making-Test-B show stronger association in females; Trail-Making-Test-A shows right-eye dominance. Findings in Trail-Making-Test-A projected to left brain-hemisphere, and the ratio incongruent to neutral in the Stroop test projected to right brain-hemisphere. Separate assessment for sex and eye-side is presented for the first time in a population-based study. Location-specific sectorial retinal nerve fiber layer thickness was found to be an indicator for cognitive performance, giving an option for early detection of cognitive decline and the potential of early treatment.

Association of retinal thickness and microvasculature with cognitive performance and brain volumes in elderly adults

“…In our present study, we showed retinal thicknesses and retinal microvasculature had a significant correlation with Stroop parameters which is in line with previous reports ( van Koolwijk et al, 2009 ; Mutlu et al, 2018 ). Our findings suggest that GCIPL thickness and SVC density may reflect cognitive dysfunction which is in line with previous reports ( Jones-Odeh et al, 2016 ; Ko et al, 2018 ; Girbardt et al, 2021 ; Kim et al, 2022 ).…”

Investigation of the Relationship Between Cognitive Functions and Retinal Findings From Spectral Optical Coherence Tomography in Patients With Schizophrenia and Their Healthy Siblings

“…A population-based study investigating 11,124 eyes of 6,471 subjects found that low cognitive performance was mainly associated with thinner RNFL thickness and suggested that RNFL thickness would be an indicator for cognitive performance and present the potential for prediction of future cognitive decline. 38 We found that both the right and left eye RNFL thickness and the Digit Span Test performances were moderately correlated in patients. The Digit Span Test evaluates working memory, 39 Similarly, in a follow-up study conducted in 2017, the thickness of the RNFL was associated with the test scores that evaluated episodic memory, and it was emphasized that the RNLF thickness could be a marker reflecting the cognitive deficits in geriatric population.…”

Association of retinal nerve layers thickness and brain imaging in healthy young subjects from the i‐Share‐Bordeaux study

“…On the other hand, studies exploring the associations between retinal layers and cognitive function in young populations are very scarce. Indeed, the previous studies that have explored these associations were mainly conducted among adults (over 40 years) (Girbardt et al, 2021; Jeevakumar et al, 2022; Khawaja et al, 2016; Ko et al, 2018; Merten et al, 2020). To our knowledge, only one previous study in this field has included young people, showing that retinal layer thickness assessed in middle age was associated with cognitive performance in childhood and adulthood (Barrett‐Young et al, 2022).…”

“…On the other hand, studies exploring the associations between retinal layers and cognitive function in young populations are very scarce. Indeed, the previous studies that have explored these associations were mainly conducted among adults (over 40 years) (Girbardt et al, 2021;Jeevakumar et al, 2022;Khawaja et al, 2016;Ko et al, 2018;Merten et al, 2020).…”