Vision Impairment Linked with High all cause mortality, finds lancet Study

The impacts of vision impairment and blindness are wide-reaching, including an increased risk of falls, cognitive impairment and dementia, depression, disability, and loss of independence. However, an improved understanding of the association between vision impairment and mortality is needed to inform public policy, public health planning, and allocation of limited health-care resources. Therefore, Dr Joshua R Ehrlich, MD and team conducted a study to systematically identify studies describing the association between vision impairment and mortality and to assess the association between vision impairment and all-cause mortality.

It was a systematic review and meta-analysis, in which researchers searched MEDLINE (Ovid), Embase, and Global Health database for prospective and retrospective cohort studies that measured the association between vision impairment and all-cause mortality in people aged 40 years or older who were followed up for 1 year or more. They identified 3845 articles, of which 28 studies, representing 30 cohorts from 12 countries and included them in the systematic review. For the meta-analysis, they included 17 studies, representing 18 cohorts. They graded the overall certainty of the evidence using the Grading of Recommendations, Assessment, Development and Evaluations framework. They conducted a random-effects meta-analysis to calculate pooled maximally adjusted hazard ratios (HRs) for all-cause mortality for individuals with a

• visual acuity of <6/12 versus those with ≥6/12;
• <6/18 versus those with ≥6/18;
• <6/60 versus those with ≥6/18; and
• <6/60 versus those with ≥6/60.

Key findings of the study were:

♦ The results support the existence of a consistent association between poor vision and mortality across different study settings. The pooled HRs for all-cause mortality were:

• 1·29 for visual acuity <6/12 versus ≥6/12, with low heterogeneity between studies (n=15); 1·43 for visual acuity <6/18 versus ≥6/18, with low heterogeneity between studies (n=2);
• 1·89 for visual acuity <6/60 versus ≥6/18 (n=1); and
• 1·02 for visual acuity <6/60 versus ≥6/60 (n=2).

♦They noted that the effect sizes did not vary in terms of risk of bias, study design, or participant-level factors and mentioned that the evidence to be of moderate certainty.

The authors concluded, "The hazard for all-cause mortality was higher in people with vision impairment compared with those that had normal vision or mild vision impairment, and the magnitude of this effect increased with more severe vision impairment. These findings have implications for promoting healthy longevity and achieving the Sustainable Development Goals."

For further information:

https://www.thelancet.com/journals/langlo/article/PIIS2214-109X(20)30549-0/fulltext