Visual Impairment, Eye Disease, and 3-Year Cognitive Decline: The Canadian Longitudinal Study on Aging

Abstract

Purpose: To examine the longitudinal association between vision-related variables and the 3-year change in cognitive test scores in a community-dwelling sample of adults and to explore whether sex, education, or hearing loss act as effect modifiers. Methods: Data came from two waves of a 3-year population-based prospective cohort study (Canadian Longitudinal Study on Aging), which consisted of 30,097 randomly selected people aged 45-85 years from 7 Canadian provinces. Visual impairment (VI) was defined as binocular presenting visual acuity worse than 20/40. Participants were asked if they had ever had a diagnosis of age-related macular degeneration (AMD), glaucoma, or cataract. Cognitive change over 3 years was examined by calculating the difference between baseline and follow-up scores for the Rey Auditory Verbal Learning Test (RAVLT) and the RAVLT delayed test (memory tests), the Controlled Oral Word Association Test (COWAT) and the Animal Naming Test (ANT) (verbal fluency tests), and the Mental Alternation Test (MAT) (processing speed test). Multiple linear regression was used. Results: VI, AMD, and cataract were not associated with 3-year changes on any of the 5 cognitive tests after adjusting for age, sex, ethnicity, education, income, smoking, diabetes, stroke, heart disease, and province. A report of glaucoma was associated with greater declines in MAT scores (β = -0.60, 95% CI -1.03, -0.18). No effect modification was detected. Conclusions: Glaucoma was associated with worsening processing speed. Further research to confirm this finding and to understand the possible reason is necessary.

Mendelian randomization study shows no causal relationship between psychiatric disorders and glaucoma in European and East Asian populations

“…However, a prospective cohort research revealed that there was no link between depression and glaucoma, which was inconsistent with findings forementioned (Vidal et al, 2021). Also, a 3-year longitudinal study consisting of 30,097 individuals aged 45-85 years did not find an association between glaucoma and depression (Grant et al, 2021). These contentious findings may be influenced by indissoluble or unidentified risk factors in observational studies.…”

“…In a recent study, retinal nerve fiber layer thinning and neural cell loss in the ganglion cell layer were observed in the chronic unpredictable mild stress mouse model, indicating that psychological stress could induce glaucoma-like changes (Zhang et al, 2022). While some other epidemiological findings suggested that there was no association between depression and glaucoma (Rezapour et al, 2018;Vidal et al, 2021;Grant et al, 2021), which made this relationship contentious. Establishing a definitive etiological link may be challenging due to the presence of confounding factors and the potential for reverse causation in traditional epidemiological findings.…”

Abnormal functional connectivity strength in age-related macular degeneration patients: a fMRI study

“…Existing research suggests that AMD is associated with functional and structural visual cortex abnormalities, as well as cognitive decline. Recent imaging studies support this by showing an association between macular degeneration and cognitive decline [14,15]. Szlyk et al also reported that patients with AMD developed abnormal cerebral network changes that increased prefrontal and parietal activation [16].…”

Roles of Cognitive Function on Visual Field Reliability Indices among Glaucoma Patients

“…Among people with glaucoma, the prevalence of MCI and dementia ranged from 12.3% to 90.2% and from 2.5% to 3.3%, respectively [10]. In a 3-year population-based prospective cohort study, glaucoma was associated with greater declines in Mental Alternation Test scores and worsening processing speed [11].…”