Vision impairment is associated with a higher risk for age-adjusted all-cause mortality in adults, researchers found in a study published in Lancet Global Health.
Several primary research articles — including from regions of the world that have received limited representation in literature — have been published since the release of the last meta-analysis of the association between vision impairment and mortality. The researchers, as part of The Lancet Global Health Commission on Global Eye Health, conducted a systematic review and meta-analysis to assess the quality of evidence of the association.
The investigators searched MEDLINE (OVID), Embase, and Global Health database from inception through February 1, 2020 for cohort studies and randomized controlled trials on the association between vision impairment and all-cause mortality among people 40 years old or older. They included studies that assessed visual acuity. Vision impairment was classified based on WHO reporting standards.
The researchers included 28 studies representing 30 cohorts (466,088 participants) from 12 countries across 5 continents in the systematic review and 17 studies representing 18 cohorts (47,998 participants) in the meta-analysis.
Compared with uncorrected refractive error, nonrefractive causes of vision impairment might have a stronger association with mortality, the report shows. Researchers speculate that the association could be attributed to common risk factors for both, such as stroke or diabetes, and that nonrefractive vision impairment could also have a greater effect on lifestyle factors that mediate the association with mortality, such as physical activity.
“Worldwide, more than 80% of people with vision impairment and blindness live in low-income and middle-income countries,” the study says. Women and girls account for 55% of that group and 4 out of 5 cases of vision impairment and blindness are preventable, or correctable. “In fact, the leading causes of vision impairment and blindness worldwide are cataract and uncorrected refractive error, both of which are readily treatable with inexpensive, cost-effective interventions,” the report adds. “Therefore, there is an important opportunity to promote not only health and wellbeing, but also longevity by correcting, rehabilitating, and preventing avoidable vision loss.”
Limitations of the study included wide variation in how studies adjusted for confounding variables. Most studies included were from high-income countries.
Disclosure: Several of the study authors declared affiliations with industry organizations and foundations.
Ehrlich JR, Ramke J, Macleod D, et al. Association between vision impairment and mortality: a systematic review and meta-analysis. Lancet Glob Health. Published online February 16, 2021. doi:10.1016/S2214-109X(20)30549-0