Vision Impairment and Participation in Cognitively Stimulating Activities: The Health ABC Study

Value proposition of retinal imaging in Alzheimer's disease screening: A review of eight evolving trends

Alzheimer's disease (AD) is the leading cause of dementia worldwide. Current diagnostic modalities of AD generally focus on detecting the presence of amyloid β and tau protein in the brain (for example, positron emission tomography [PET] and cerebrospinal fluid testing), but these are limited by their high cost, invasiveness, and lack of expertise. Retinal imaging exhibits potential in AD screening and risk stratification, as the retina provides a platform for the optical visualization of the central nervous system in vivo, with vascular and neuronal changes that mirror brain pathology. Given the paradigm shift brought by advances in artificial intelligence and the emergence of disease-modifying therapies, this article aims to summarize and review the current literature to highlight 8 trends in an evolving landscape regarding the role and potential value of retinal imaging in AD screening.

Digital Technology Use Among Older Adults With Vision Impairment

Importance

Telehealth has the potential to improve health for older adults, but many access disparities exist, including for those with vision impairment (VI).

Objective

To examine the associations between VI and digital technology access measures in US older adults.

Design, Setting, and Participants

This was a cross-sectional study that included Medicare beneficiaries 65 years and older. Beneficiary data were obtained from the National Health and Aging Trends Study (NHATS) 2021; data collection was conducted from June 2020 through January 2021. Data were analyzed September 2023.

Exposure

VI, measured on categorical (distance and near VI [>0.30 logMAR], contrast sensitivity impairment [CSI; <1.55 logCS], and any VI [distance VI, near VI, or CSI]), and continuous (distance and near acuity [logMAR] and contrast sensitivity [logCS]) scales.

Main Outcomes

Self-reported outcomes of digital technology access from the technological environment component of the NHATS.

Results

Of the 2822 Medicare beneficiaries (mean [SD] age, 78.5 [5.6] years; 1605 female [54.7%]) included in this study, patients self-identified with the following race and ethnicity categories (weighted percentages): 575 non-Hispanic Black (8.0%), 132 Hispanic (7.0%), 2019 non-Hispanic White (81.7%), and 63 non-Hispanic other race (3.4%), which included American Indian, Alaska Native, Asian, multiracial, Native Hawaiian, Pacific Islander, or other specified race. A total of 1077 of 2822 patients (32.3%) had any VI. In multivariable logistic regression models, older adults with any VI had lower odds of having or knowing how to use a cellphone (odds ratio [OR], 0.58; 95% CI, 0.38-0.88), computer (OR, 0.61; 95% CI, 0.47-0.79), or tablet (OR, 0.68, 95% CI = 0.54-0.85) than peers without VI. In other models, near VI was associated with lower odds of having and knowing how to use a phone (OR, 0.56; 95% CI, 0.36-0.87), computer (OR, 0.57; 95% CI, 0.44-0.75), or tablet (OR, 0.65; 95% CI, 0.52-0.81) compared with no near VI. CSI was associated with lower odds of having and knowing how to use a phone (OR, 0.66; 95% CI, 0.45-0.99) or computer (OR, 0.72; 95% CI, 0.55-0.93) compared with no CSI. Distance VI was only associated with lower odds of having and knowing how to use a cellphone (OR, 0.63; 95% CI, 0.41-0.95). Any VI and individual categorical VI measures were not associated with other outcomes of digital health- and nonhealth-related experiences. Similar associations were noted when vision was examined on a continuous scale. However, worse distance acuity (per 0.1 logMAR) was associated with being less likely to visit with family or friends on a video call (OR, 0.91; 95% CI, 0.84-0.98) and to order or refill prescriptions online (OR, 0.90; 95% CI, 0.83-0.97).

Conclusions and Relevance

Results suggest that older US adults with VI were less likely to have access to digital technology than peers without VI, although no differences were noted in the report of digital health- and nonhealth-related activities. These findings highlight the potential for inequities that may arise in telehealth for older adults with VI and the necessity to develop strategies to improve accessibility of telemedicine for all.

Association between vision impairment and increased prevalence of falls in older US adults

BACKGROUND

Vision impairment (VI) is associated with falls in older adults. However, past studies have relied on geographically constrained samples with limited generalizability or self-reports of visual difficulty. To date, there have not been nationally representative studies on the association of objective measures of visual function and falls outcomes.

METHODS

We used cross-sectional data from Round 11 of National Health and Aging Trends Study (NHATS), a nationally representative panel study of age-eligible Medicare beneficiaries (N = 2951). We performed Poisson regression to calculate the prevalence and prevalence ratio (PR) of >1 fall in the past year, any fall in the past month, fear of falling (FoF), and activity limitation due to FoF as a function of distance visual acuity, near visual acuity, and contrast sensitivity. Models were adjusted for demographic and health covariates and were weighted to make nationally representative parameter estimates.

RESULTS

The weighted proportion of participants with VI was 27.6% (95% CI, 25.4%-29.9%). Individuals with any VI had a higher prevalence of falls compared with those without VI (18.5% vs. 14.1%, PR = 1.25, 95% CI 1.02-1.53). Specifically, contrast sensitivity impairment was associated with a higher prevalence of recurrent falls (20.8% vs. 14.7%; PR = 1.30, 95% CI 1.01-1.67) and recent falls (17.1% vs. 9.9%; PR = 1.40, 95% CI 1.01-1.94). This relationship existed even independent of near and distance visual acuity. Distance and near visual acuity were not significantly associated with falls. Having any VI was also associated with a higher prevalence of FoF (38.4% vs. 30.5%, PR = 1.17, 95% CI 1.02-1.34).

CONCLUSION

The prevalence of falls is associated with poor contrast sensitivity but not with near or distance visual acuity. Findings suggest greater collaboration between geriatricians and eye care providers may be warranted to assess and address fall risk in older adults with VI.

Associations Between Self-Reported Visual Difficulty, Age of Onset, and Cognitive Function Trajectories Among Chinese Older Adults

Objectives: This study examined the association between self-reported visual difficulty and age-related cognitive declines among older Chinese adults and how the timing of visual difficulty onset plays a role in cognitive trajectories. Methods: Data were drawn from the 2011-2018 wave of the China Health and Retirement Longitudinal Study, involving 9974 respondents aged 60 years or older (mean age 65.44 years, range 60-101 years). Results: At baseline, 14.16% respondents had self-reported visual difficulty. Growth curve models showed that Chinese older adults with visual difficulty experienced a faster decline in cognitive function compared to those without visual difficulty (β = -0.02, p < .01). Older adults who began experiencing visual difficulty between 61 and 75 years of age had steeper cognitive declines compared to those with earlier or later onset (β = -0.05, p < .01). Discussion: Older adults with self-reported visual difficulty experience faster rates of cognitive decline. Future research should explore potential factors that underlie the association between onset timing of visual difficulty and cognitive function.

Resolving heterogeneity in Alzheimer's disease based on individualized structural covariance network

The heterogeneity of Alzheimer's disease (AD) poses a challenge to precision medicine. We aimed to identify distinct subtypes of AD based on the individualized structural covariance network (IDSCN) analysis and to research the underlying neurobiology mechanisms. In this study, 187 patients with AD (age = 73.57 ± 6.00, 50% female) and 143 matched normal controls (age = 74.30 ± 7.80, 44% female) were recruited from the Alzheimer's Disease Neuroimaging Initiative (ADNI) project database, and T1 images were acquired. We utilized the IDSCN analysis to generate individual-level altered structural covariance network and performed k-means clustering to subtype AD based on structural covariance network. Cognition, disease progression, morphological features, and gene expression profiles were further compared between subtypes, to characterize the heterogeneity in AD. Two distinct AD subtypes were identified in a reproducible manner, and we named the two subtypes as slow progression type (subtype 1, n = 104, age = 76.15 ± 6.44, 42% female) and rapid progression type (subtype 2, n = 83, age = 71.98 ± 8.72, 47% female), separately. Subtype 1 had better baseline visuospatial function than subtype 2 (p < 0.05), whereas subtype 2 had better baseline memory function than subtype 1 (p < 0.05). Subtype 2 showed worse progression in memory (p = 0.003), language (p = 0.003), visuospatial function (p = 0.020), and mental state (p = 0.038) than subtype 1. Subtype 1 often shared increased structural covariance network, mainly in the frontal lobe and temporal lobe regions, whereas subtype 2 often shared increased structural covariance network, mainly in occipital lobe regions and temporal lobe regions. Functional annotation further revealed that all differential structural covariance network between the two AD subtypes were mainly implicated in memory, learning, emotion, and cognition. Additionally, differences in gray matter volume (GMV) between AD subtypes were identified, and genes associated with GMV differences were found to be enriched in the terms potassium ion transport, synapse organization, and histone modification and the pathways viral infection, neurodegeneration-multiple diseases, and long-term depression. The two distinct AD subtypes were identified and characterized with neuroanatomy, cognitive trajectories, and gene expression profiles. These comprehensive results have implications for neurobiology mechanisms and precision medicine.

Population prevalence of dual sensory loss in community-dwelling US adults 71 years and older: Evidence from the National Health and Aging Trends Study

BACKGROUND

Existing estimates for the prevalence of dual sensory loss (vision and hearing) among older adults are either based on self-reported measures or aggregated for older age groups. Current and detailed estimates based on objective measures are needed for public health, clinical, and policy decision-making.

METHODS

We estimated the prevalence of dual sensory loss (DSL) using National Health Aging Trends Study (NHATS) Round 11 data (2021). We restricted to community-dwelling adults aged ≥71 years with complete sensory testing data (N = 2579). Hearing loss was defined by a 4-frequency (0.5, 1, 2 and 4 kHz) pure tone average for the better-hearing ear (>25 decibel hearing level). Vision loss was defined by the presence of distance, near (logarithm of the minimum angle of resolution >0.30), or contrast sensitivity loss (log contrast sensitivity <1.55). Participants were categorized into three groups: no sensory loss, single sensory loss (vision or hearing loss), and DSL (hearing and vision). Sensory loss prevalence was estimated by age group and sociodemographic characteristics.

RESULTS

In weighted analyses, among older Medicare beneficiaries (53% female, 7% Black, 6% Hispanic), 28% had no sensory loss and 22% had DSL. Prevalence of DSL increased with age. Most adults aged ≥90 years experienced DSL (59%), as opposed to single (39%) or no sensory loss (2%). DSL prevalence was greater among older adults with low education attainment (34%) and household income (43%). A higher proportion of older adults with a college education (17%), or from wealthier households (16%), had no sensory loss.

CONCLUSIONS

One in 5 community-dwelling Medicare beneficiaries aged ≥71 years have DSL, increasing to 3 in 5 for those aged ≥90 years. Prevalence is higher among older adults with low education attainment and from low-income households, characteristics associated with low treatment. Policies increasing access and affordability of vision and hearing care could benefit millions of older Americans experiencing sensory loss.

Using Objective Vision Measures to Explore the Association of Vision Impairment With Cognition Among Older Adults in the United States

PURPOSE

To evaluate the association between vision impairment (VI) and cognitive function using objective measures.

DESIGN

Cross-sectional analysis with a nationally representative sample.

METHODS

The association between VI and dementia was investigated in a US population-based, nationally representative sample of Medicare beneficiaries, the National Health and Aging Trends Study (NHATS), a nationally representative sample of Medicare beneficiaries aged ≥65 years, using objective vision measures. Exposures included distance VI (>20/40), near VI (>20/40), contrast sensitivity impairment (CSI) (<1.55), any objective VI (distance and near visual acuity, or contrast), and self-reported VI. The main outcome measure was dementia status defined based on survey reports, interviews, and cognitive tests.

RESULTS

A total of 3026 adults were included in this study; the majority were female (55%) and White (82%). The weighted prevalence rates were 10% for distance VI, 22% for near VI, 22% for CSI, 34% for any objective VI, and 7% for self-reported VI. Across all measures of VI, dementia was more than twice as prevalent in adults with VI compared to their peers without (P < .001 for all). In adjusted models, all measures of VI were associated with higher odds of dementia (distance VI: OR 1.74, 95% CI 1.24-2.44; near VI: OR 1.68, 95% CI 1.29-2.18; CSI: OR 1.95, 95% CI 1.45-2.62; any objective VI: OR 1.83, 95% CI 1.43-2.35; self-reported VI: OR 1.86, 95% CI 1.20-2.89).

CONCLUSIONS

In a nationally representative sample of older US adults, VI was associated with increased odds of dementia. These results suggest that maintaining good vision and eye health may help preserve cognitive function in older age, although more research is needed to investigate the potential benefits of interventions that focus on vision and eye health on cognitive outcomes.

The Association Between Eye Disease and Incidence of Dementia: Systematic Review and Meta-Analysis

OBJECTIVES

To better demonstrate the relationship between common eye diseases and the risk of dementia, we conducted a systematic review and meta-analysis of cohort studies to investigate the relationship between common eye diseases and dementia.

DESIGN

Systematic review and meta-analysis.

SETTING AND PARTICIPANTS

Patients with common eye diseases.

METHODS

We conducted a systematic search of articles published up to August 25, 2022, of online databases including PubMed, EMBASE, and Web of Science. We included cohort studies that evaluated the association of glaucoma, age-related macular degeneration (AMD), diabetic retinopathy (DR), and cataracts with all-cause dementia, Alzheimer's disease (AD), and vascular dementia (VaD). Relative risks (RRs) and 95% CIs were pooled using random effects model, and heterogeneity was assessed by the I2 statistic. Subgroup analysis and sensitivity analysis were also performed.

RESULTS

In total, 25 studies were included in the meta-analysis, with a total of 11,410,709 participants. Pooled estimates suggested an increased risk of all-cause dementia associated with AMD (RR, 1.29; 95% CI, 1.13-1.48), glaucoma (RR, 1.16; 95% CI, 1.03-1.32), DR (RR, 1.40; 95% CI, 1.21-1.63), and cataract (RR,1.23; 95% CI, 1.09-1.40); an increased risk of AD associated with AMD (RR, 1.27; 95% CI, 1.06-1.52), glaucoma (RR, 1.18; 95% CI, 1.02-1.38), DR (RR, 1.21; 95% CI, 1.04-1.41), and cataracts (RR,1.22; 95% CI, 1.07-1.38). No association was observed between incident VaD and any eye diseases. The results of subgroup analyses were consistent with those in meta-analysis of DR and risk of all-cause dementia. Meta-regressions suggested geographic regions as potential sources of heterogeneity for the association between AMD and all-cause dementia, AMD and AD, glaucoma and dementia, glaucoma, and AD, respectively.

CONCLUSIONS AND IMPLICATIONS

AMD, glaucoma, DR, and cataract may be associated with an increased risk of all-cause dementia and AD, but not VaD. However, the results should be interpreted cautiously because of the high heterogeneity and unstable findings in some subgroup analyses.

Gender differences in the association between sensory function and CIND among Chinese elderly: Based on CLHLS

OBJECTIVE

To explore the gender differences of the association between sensory impairment (SI) and the risk of cognitive decline and possible cognitive impairment, no dementia (CIND).

METHOD

Data were drawn from three waves of the nationally representative survey of China Longitudinal Healthy Longevity Survey (CLHLS) between 2011/12-2018 surveys, involving 6138 participants aged 65 or older who had no CIND at the baseline. Multivariate linear or logistic regression models were employed to examine the effect of SI on cognitive decline and CIND risk by gender stratification, respectively.

RESULTS

Hearing impairment and visual impairment were associated with lower MMSE scores, and the strength of the association was stronger in men than in women. Hearing impairment was related to an elevated risk of CIND both in men and women (Men: OR=2.46; 95% CI=1.81, 3.35; Women: OR=1.43; 95% CI=1.09, 1.88). However, the effect of visual impairment on CIND was statistically significant only in men (OR=1.43; 95% CI=1.09, 1.88). The risk of cognitive decline and CIND were significantly higher with single and dual SI than those without SI, except for women with single visual impairment.

CONCLUSION

SI is independently associated with cognitive decline and CIND risk, and the association differed by gender. Further researches should clarify the mechanism between SI and cognitive function among older adults, especially for gender differences.

Population Prevalence of Vision Impairment in US Adults 71 Years and Older: The National Health and Aging Trends Study

Importance

Existing estimates of the prevalence of vision impairment (VI) in the United States are based on self-reported survey data or measures of visual function that are at least 14 years old. Older adults are at high risk for VI and blindness. There is a need for up-to-date, objectively measured, national epidemiological estimates.

Objective

To present updated national epidemiological estimates of VI and blindness in older US adults based on objective visual function testing.

Design, Setting, and Participants

This survey study presents a secondary data analysis of the 2021 National Health and Aging Trends Study (NHATS), a population-based, nationally representative panel study of Medicare beneficiaries 65 years and older. NHATS includes community-dwelling older adults or their proxies who complete in-person interviews; annual follow-up interviews are conducted regardless of residential status. Round 11 NHATS data were collected from June to November 2021, and data were analyzed in August 2022.

Interventions

In 2021, NHATS incorporated tablet-based tests of distance and near visual acuity and contrast sensitivity with habitual correction.

Main Outcomes and Measures

National prevalence of impairment in presenting distance visual acuity (>0.30 logMAR, Snellen equivalent worse than 20/40), presenting near visual acuity (>0.30 logMAR, Snellen equivalent worse than 20/40), and contrast sensitivity (>1 SD below the sample mean). Prevalence estimates stratified by age and socioeconomic and demographic data were calculated.

Results

In the 2021 round 11 NHATS sample, there were 3817 respondents. After excluding respondents who did not complete the sample person interview (n = 429) and those with missing vision data (n = 362), there were 3026 participants. Of these, 29.5% (95% CI, 27.3%-31.8%) were 71 to 74 years old, and 55.2% (95% CI, 52.8%-57.6%) were female respondents. The prevalence of VI in US adults 71 years and older was 27.8% (95% CI, 25.5%-30.1%). Distance and near visual acuity and contrast sensitivity impairments were prevalent in 10.3% (95% CI, 8.9%-11.7%), 22.3% (95% CI, 20.3%-24.3%), and 10.0% (95% CI, 8.5%-11.4%), respectively. Older age, less education, and lower income were associated with all types of VI. A higher prevalence of near visual acuity and contrast sensitivity impairments was associated with non-White race and Hispanic ethnicity.

Conclusions and Relevance

More than 1 in 4 US adults 71 years and older had VI in 2021, higher than prior estimates. Differences in the prevalence of VI by socioeconomic and demographic factors were observed. These data could inform public health planning.

Cognitive dysfunctions in high myopia: An overview of potential neural morpho-functional mechanisms

Dementia and cognitive impairment (CIM) carry high levels of mortality. Visual impairment (VI) is linked with CIM risk. High myopia (HM) is a chronic disease frequently leading to irreversible blindness. Current opinion has shifted from retinal injury as the cause of HM to the condition being considered an eye-brain disease. However, the pathogenesis of this disease and the manner in which neural structures are damaged are poorly understood. This review comprehensively discusses the relationship between HM, the central nervous system, and CIM, together with the novel concept of three visual pathways, and possible research perspectives.

The Longitudinal Association of Late-Life Visual and Hearing Difficulty and Cognitive Function: The Role of Social Isolation

OBJECTIVES

Sensory impairments are prevalent among older adults and have been associated with cognitive challenges in later life, yet mechanisms are less well understood. We examined the mediating role of social isolation in the longitudinal relationship between self-reported sensory difficulty and impaired cognitive functioning among older adults.

METHODS

Data were taken from the NHATS Study, an annual survey of Medicare beneficiaries' age ≥ 65. Participants (N = 6,338) provided data at Rounds 5, 6, and 7 (2015, 2016, 2017). Structural equation models were estimated to test longitudinal direct and indirect associations.

RESULTS

All sensory difficulties were negatively associated with all cognitive functioning measures cross-sectionally through social isolation. Longitudinally, vision difficulty and dual sensory difficulty were indirectly associated with cognitive functioning across time. Hearing difficulty had no longitudinal indirect associations with cognitive functioning through social isolation.

DISCUSSION

Social isolation is an important pathway through which late-life vision difficulty is associated with decreased cognitive function.

Vision Impairment and Adverse Health Conditions in Congolese Older People: A Population-Based Study

INTRODUCTION

In sub-Saharan Africa, many older people experience vision impairment (VI) and its adverse health outcomes. In this study, we examined separately the association between VI and each adverse health conditions (cognitive disorders, vision-related quality of life [VRQoL], and daily functioning interference [DFI]) among Congolese older people. We also explored whether VI had a significant effect on VRQoL components in our population.

METHOD

We performed cross-sectional analyses on data from 660 Congolese people aged ≥65 years who participated in the 2013 survey of the EPIDEMCA population-based cohort study. VI was defined as having a near visual acuity <20/40 (assessed at 30 cm using a Parinaud chart). Cognitive disorders were assessed using neuropsychological tests and neurological examinations. VRQoL was assessed using a reduced version of the National Eye Institute Visual Function Questionnaire (VFQ-22) and DFI using 11 items of participation restrictions and activity limitations. Regarding our main objective, each association was explored separately using multivariable logistic and linear regression models. Additionally, the effects of VI on each VRQoL components were explored using univariable linear regression models.

RESULTS

VI was not associated with cognitive disorders after adjustment for residence area (adjusted odds ratio = 1.7; 95% confidence interval [CI]: 0.6; 4.7), but it was associated with a low VRQoL score (adjusted β = -12.4; 95% CI: -17.5; -7.3) even after controlling for several covariates. An interaction between VI and age (p = 0.007) was identified, and VI was associated with DFI only among people aged >73 years (adjusted β = 0.5; 95% CI: 0.2; 0.8). Our exploratory analysis showed that all components of VRQoL decreased with a decrease in visual acuity (corrected p ≤ 0.05).

CONCLUSION

VI was associated with poor VRQoL and high DFI. Residence area seems to play a confounding role in the association between VI and cognitive disorders. Our findings suggest that targeting interventions on vision could reduce DFI among older people and improve their well-being.

Association of Vision Impairment With Cognitive Decline Across Multiple Domains in Older Adults

IMPORTANCE

Associations between visual and global cognitive impairments have been previously documented, but there is limited research examining these associations between multiple measures of vision across cognitive domains.

OBJECTIVE

To examine the association between vision and cognitive across multiple cognitive domains using multiple measures of vision.

DESIGN, SETTING, AND PARTICIPANTS

This longitudinal cohort study used data from the Baltimore Longitudinal Study of Aging for 2003 to 2019. Participants in the current study were aged 60 to 94 years with vision and cognitive measures. Data analysis was performed from May 2020 to May 2021.

MAIN OUTCOMES AND MEASURES

Cognitive function was measured across multiple domains, including language, memory, attention, executive function, and visuospatial ability. Cognitive domain scores were calculated as the mean of standardized cognitive test scores within each domain. Visual function was assessed using measures of visual acuity, contrast sensitivity, and stereo acuity at baseline.

RESULTS

Analyses included 1202 participants (610 women [50.8%]; 853 White participants [71.0%]) with a mean (SD) age of 71.1 (8.6) years who were followed up for a mean (SD) of 6.9 (4.7) years. Worse visual acuity (per 0.1 logarithm of the minimal angle of resolution) at baseline was associated with greater declines in language (β, -0.0035; 95% CI, -0.007 to -0.001) and memory (β, -0.0052; 95% CI, -0.010 to -0.001) domain scores. Worse contrast sensitivity (per 0.1 log units) at baseline was associated with greater declines in language (β, -0.010; 95% CI, -0.014 to -0.006), memory (β, -0.009; 95% CI, -0.015 to -0.003), attention (β, -0.010; 95% CI, -0.017 to -0.003), and visuospatial ability (β, -0.010; 95% CI, -0.017 to -0.002) domain scores. Over the follow-up period, declines on tests of language (β, -0.019; 95% CI, -0.034 to -0.005) and memory (β, -0.032; 95% CI, -0.051 to -0.012) were significantly greater for participants with impaired stereo acuity compared with those without such impairment.

CONCLUSIONS AND RELEVANCE

These findings suggest that the association between vision and cognition differs between visual acuity, contrast sensitivity, and stereo acuity and that patterns of cognitive decline may differ by type of vision impairment, with impaired contrast sensitivity being associated with declines across more cognitive domains than other measures of visual functioning.

The Bidirectional Relationship between Vision and Cognition: A Systematic Review and Meta-analysis

TOPIC

Visual impairment (VI) and cognitive impairment (CIM) are prevalent age-related conditions that impose substantial burden on the society. Findings on the hypothesized bidirectional association of VI and CIM remains equivocal. Hence, we conducted a systematic review and meta-analysis to examine this bidirectional relationship.

CLINICAL RELEVANCE

Sixty percent risk of CIM has not been well elucidated in the literature. A bidirectional relationship between VI and CIM may support the development of strategies for early detection and management of risk factors for both conditions in older people.

METHODS

PubMed, Embase, and Cochrane Central registers were searched systematically for observational studies, published from inception until April 6, 2020, in adults 40 years of age or older reporting objectively measured VI and CIM assessment using clinically validated cognitive screening tests or diagnostic evaluation. Meta-analyses on cross-sectional and longitudinal associations between VI and CIM outcomes (any CIM assessed using screening tests and clinically diagnosed dementia) were examined. Random effect models were used to generate pooled odds ratios (ORs) and 95% confidence intervals (CIs). We also examined study quality, publication bias, and heterogeneity.

RESULTS

Forty studies were included (n = 47 913 570). Meta-analyses confirmed that persons with VI were more likely to have CIM, with significantly higher odds of: (1) any CIM (cross-sectional: OR, 2.38 [95% CI, 1.84-3.07]; longitudinal: OR, 1.66 [95% CI, 1.46-1.89]) and (2) clinically diagnosed dementia (cross-sectional: OR, 2.43 [95% CI, 1.48-4.01]; longitudinal: OR, 2.09 [95% CI, 1.37-3.21]) compared with persons without VI. Significant heterogeneity was explained partially by differences in age, sex, and follow-up duration. Also, some evidence suggested that individuals with CIM, relative to cognitively intact persons, were more likely to have VI, with most articles (8/9 [89%]) reporting significantly positive associations; however, meta-analyses on this association could not be conducted because of insufficient data.

DISCUSSION

Overall, our work suggests that VI is a risk factor of CIM, although further work is needed to confirm the association of CIM as a risk factor for VI. Strategies for early detection and management of both conditions in older people may minimize individual clinical and public health consequences.