Researchers here note an association between vision impairment and mortality in later life. This has the look of a correlation that exists because aging is a global process at work throughout the body. It stems from the accumulation of a few classes of cell and tissue damage. That damage causes downstream consequences that spread out into a complex, diverse array of degeneration and diseases. If vision is failing more rapidly in any given individual, then the odds are very good that this is also the case for other, more critical systems in the body.
For this systematic review and meta-analysis, we searched 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. In a protocol amendment, we also included randomised controlled trials that met the same criteria as for cohort studies, in which the association between visual impairment and mortality was independent of the study intervention. Our searches identified 3845 articles, of which 28 studies, representing 30 cohorts (446,088 participants) from 12 countries, were included in the systematic review.
There was variability in the methods used to assess and report vision impairment. Pooled hazard ratios for all-cause mortality were 1.29 for visual acuity <6/12 versus ≥6/12; 1.43 for visual acuity <6/18 versus ≥6/18; 1.89 for visual acuity <6/60 versus ≥6/18; and 1.02 for visual acuity <6/60 versus ≥6/60. Effect sizes were greater for studies that used best-corrected visual acuity compared with those that used presenting visual acuity as the vision assessment method, but the effect sizes did not vary in terms of risk of bias, study design, or participant-level factors (ie, age). We judged the evidence to be of moderate certainty.
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.