Cataract Surgery May Reduce Alzheimer’s Risk: Study

A team of American researchers has found evidence that cataract surgery may be linked to a lower risk of developing dementia, especially Alzheimer’s disease, in older people.

The observational study, based on data from over 3000 participants aged over 65, found that people who had cataract surgery had an almost 30% lower risk of developing dementia from any cause than those who had not.

Cataract surgery was also associated with a lower risk of Alzheimer’s disease in particular.

The results, reported on December 6 in JAMA Internal Medicinesuggest that this reduced risk persisted for at least a decade after undergoing surgery.

“This type of evidence is as good as it gets in epidemiology,” lead researcher Dr. Cecilia Lee said in a press release. “This is really exciting because no other medical intervention has shown such a strong association with the decreased risk of dementia in the elderly.”

Study data was provided by the Adult Changes in Thought (ACT) study – a long-standing Seattle-based observational study at Kaiser Permanente Washington, consisting of more than 5,000 participants over the age of 65.

The researchers followed participants diagnosed with cataracts or glaucoma who did not have dementia or had not had cataract surgery when they volunteered for the study. Participants were assessed every two years for their cognitive abilities.

Of 3,038 participants, 853 subjects developed dementia during a seven-year follow-up period, of which 709 were diagnosed with Alzheimer’s. About half of the participants underwent cataract surgery.

Although the study did not establish a direct link between cataract surgery and a decreased risk of dementia, the researchers hypothesize that those who had the surgery may have achieved better sensory input. thanks to their improved vision.

“These findings are consistent with the idea that sensory input to the brain is important for brain health,” co-author Dr. Eric B. Larson said in a press release.

Another hypothesis is that the eye receives more blue light after cataract surgery.

“There are special cells in the retina that are associated with cognition and regulate sleep cycles, and these cells respond well to blue light,” Lee said. “Cataracts specifically block blue light, and cataract surgery could reactivate these cells.”

Researchers adjusted a long list of factors, including health-related confounders, including hypotheses that participants who had cataract surgery might have been healthier and at lower risk of dementia. initially, but still found strong associations when these factors were taken into account.

Eye surgeries performed within two years of being diagnosed with dementia have been ruled out because of the possibility that people with cognitive decline may have been less aware of vision problems.

Even excluding this group, the researchers found lower risks of dementia associated with cataract surgery.

Previous research on the risks of dementia has shown similar results.

A 2020 study by researchers at the University of Michigan found that hearing aid use may be associated with a reduced risk of dementia. The study found that older people who received hearing aids within three years of being diagnosed with hearing loss had lower rates of dementia, depression and even falls than those without hearing aids.