People with cataract-related vision loss who have had cataract surgery are living longer than those with visual impairment who chose not to have the procedure. After comparing the two groups, researchers found a 40 per cent lower long-term mortality risk in those who had the surgery.

The research is drawn from data gathered in the Blue Mountains Eye Study, a population-based cohort study of vision and common eye diseases in an older Australian population. A total of 354 people aged 49 years and older and diagnosed with cataract-related vision impairment - some of whom had undergone surgery and others who had not - were assessed between 1992 and 2007.

Adjustments were made for age and gender as well as a number of mortality risk factors, including hypertension, diabetes, smoking, cardiovascular disease, Body Mass Index and measures of frailty and co-morbid disease. Follow-up visits took place five and ten years after the baseline exam.

Previous research had indicated that older people with visual impairment were likely to have greater mortality risk than their age peers with normal vision, and that cataract surgery might reduce this risk. These studies - unlike the Blue Mountains Eye Study - compared people who had undergone cataract surgery with those in the general population or with those who had not had cataract surgery, and did not link vision status to the surgical status.

The association between correction of cataract-related visual impairment and reduced mortality risk is not clearly understood, but plausible factors may include improvements in physical and emotional well-being, optimism, greater confidence associated with independent living after vision improvement, as well as greater ability to comply with prescription medication.