Older women who undergo cataract surgery may live longer.
The researchers report their findings, which drew on data from the Women's Health Initiative (WHI), in the journal JAMA Ophthalmology. The WHI is a nationwide study of postmenopausal women in the United States aged between 50 and 79 years.
Senior study author Anne L. Coleman — a professor of ophthalmology at the University of California, Los Angeles — and team explain that previous studies have shown that, as well as enjoying better vision, individuals with cataracts who have cataract surgery also seem to have a lower risk of dying prematurely.
But to their knowledge, nobody had yet looked at the link between cataract surgery and cause-specific rates of death. To this end, they chose to study participants in the WHI because it contains health data that are "not available in other large databases of patients with cataract surgery in the [U.S.]"
A cataract is an eye condition that is common in older people. It develops when the lens of the eye becomes cloudy, resulting in loss of sharpness and blurring of vision. To see clearly, the lens — which focuses light onto the retina — should be transparent.
Lower risk of death
More than half of U.S. adults older than 80 have a cataract or have had cataract surgery, which is a normally straightforward procedure that replaces the damaged lens with an artificial one.
The WHI database — which contains information on total and cause-specific deaths — is also linked to the Medicare claims database. This allowed the researchers to select data on WHI participants aged 65 and over who had been diagnosed with cataract. The WHI data covered the period from the start of 1993 to the end of 2015.
The scientists found that the WHI contained 74,044 women aged 65 and over, aged 71, on average, who had been diagnosed with cataracts. This number included 41,735 women who had undergone cataract surgery.
When they analyzed the data, the team found that having had cataract surgery was linked to a 60 percent lower risk of death from all causes.
They also found that cataract surgery was tied to reduced risk of death from specific causes that ranged from 37 percent to 69 percent. The specific causes were cancer as well as pulmonary, accidental, neurologic, infectious, and vascular diseases.
The authors note that because the study was limited to women, it does mean that the findings might be true for men.
The researchers also point out that just because they found lower rates of death in the cataract surgery group, it does not prove that having cataract surgery extends life.
It is now for further research to investigate the "interplay of cataract surgery, systemic disease, and disease-related mortality," they write, noting that such studies "would be informative for improved patient care."
The team does, however, mention some studies that have offered explanations for the link between cataract surgery and lower risk of death.
For example, some research has shown that people who have cataract surgery have a "lower risk for fall and fracture," while other studies have found that patients have "higher scores on standardized cognition assessments after cataract surgery."
In terms of their own results, the team notes that the participants who underwent cataract surgery tended to have a higher socioeconomic status. This could mean that they were more likely to be receiving better healthcare, which, in turn, might affect the risk of premature death.
Finally, they also raise the possibility that participants in the cataract surgery group may have had healthier lifestyles, and they suggest that:
"The incorporation of additional lifestyle factors with variables such as the WHI healthy diet score would be of importance and interest for future studies."