Cataract surgery was linked to 29 percent less dementia

Researchers running a long-term Seattle study called Adult Changes in Thought followed thousands of older adults for years, tracking who developed cataracts, who had them removed, and who later developed dementia.

Among 3,038 participants with cataract or glaucoma, Cecilia Lee's team at the University of Washington found that those who had cataract surgery were about 29 percent less likely to be diagnosed with dementia than those who did not, a gap that held after adjusting for health and education. Removing cloudy lenses from the eyes, not the surgery itself, seemed to matter.

As a check, the researchers looked at glaucoma surgery, which did not lower dementia risk, suggesting clearer vision itself, not contact with the health system, explained the pattern. Still, this was an observational study, not a randomized trial. People who get cataract surgery may simply be healthier to begin with, so the link is a strong association, not proof of cause.

An association, not yet a cause.