Eye disease and mortality, cognition, disease, and modifiable risk factors: an umbrella review of meta-analyses of observational studies

Globally, 2.2 billion people live with some form of vision impairment and/or eye disease. To date, most systematic reviews examining associations have focused on a single eye disease and there is no systematic evaluation of the relationships between eye diseases and diverse physical and mental health outcomes. Moreover, the strength and reliability of the literature is unclear. We performed an umbrella review of observational studies with meta analyses for any physical and/or mental comorbidities associated with eye disease. For each association, random-effects summary effect size, heterogeneity, small-study effect, excess significance bias and 95% prediction intervals were calculated, and used to grade significant evidence from convincing to weak. 34 studies were included covering 58 outcomes. No outcomes yielded convincing evidence, six outcomes yielded highly suggestive results (cataract positively associated with type 2 diabetes, open-angled glaucoma positively associated with myopia and diabetes, diabetic retinopathy positively associated with cardiovascular disease and cardiovascular mortality, and retinopathy of prematurity positively associated with chorioamnionitis), eight outcomes yielded suggestive results (diabetic retinopathy positively associated with all-cause mortality and depression, diabetic macular oedema positively associated with dyslipidaemia, cataract positively associated with gout, nuclear sclerosis positively associated with all-cause mortality, open angled glaucoma positively associated with migraine and hypertension, and age-related macular degeneration positively associated with diabetes), and 18 outcomes yielded weak evidence. Results show highly suggestive or suggestive evidence for associations between several types of eye diseases with several comorbid outcomes. Practitioners and public health policies should note these findings when developing healthcare policies.