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

Authors Tai Anh Vu, Eva Fenwick, Alfred Gan, Ryan Man, Benjamin Tan, Preeti Gupta, Kam Chun Ho, Carlos Reyes-Ortiz, Stella Trompet, Jacobijn Gussekloo, Joan O'Brien, Sigrid Mueller-Schotte, Tien Yin Wong, Yih Chung Tham, Ching-Yu Cheng, Allen Lee, Greta Rait, Bonnielin Swenor, Varshini Varadaraj, Willa Brenowitz, Felipe Medeiros, Virginie Naël, Kaavya Narasimhalu, Christopher Chen, Ecosse Lamoureux
Published in Ophthalmology
Publication date 2021
Research groups Technology for Healthcare Innovations
Type Article

Summary

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.

Language English
Published in Ophthalmology
Year and volume 128 7
Key words bidirectional, cognitive impairment, dementia, visual acuity, visual impairment
Page range 981-992

Technology for Healthcare Innovations