Cataract surgery associated with a lower risk of developing dementia

07 December 2021

Researchers from the University of Washington have found that people who had cataract surgery had a lower risk of developing Alzheimer’s disease and other dementias compared to those who did not. Findings are published today (Monday 6 December) in the journal JAMA Internal Medicine.

What are cataracts?

Cataracts are a type of eye condition that causes clouding of the lens, so vision becomes impaired. This can be fixed with surgery to replace the lens and restore vision.

What did the scientists do?

The US researchers used data from around 3,000 participants over the age of 65, who were taking part in the long-standing Adult Changes in Thought (ACT) study.

They looked at people with a cataract or glaucoma but who did not have a diagnosis of dementia or had undergone cataract surgery when they volunteered for the study.

Every two years participants had specialised cognitive tests, with those performing less well having more detailed tests as well.

What did the scientists find?

Out of the 3,038 people in the study, 853 went on to develop dementia, with the majority of these (709 people) developing Alzheimer’s disease.

Nearly half of the participants (1,382 people) had cataract surgery during the study period.

People who underwent cataract surgery had nearly 30% lower risk of developing dementia for at least 10 years after surgery compared to those who did not. Having cataract surgery was also specifically associated with a lower risk of developing Alzheimer’s disease.

Our expert comment:

Dr Sara ImarisioDr Sara Imarisio, Head of Research at Alzheimer’s Research UK, said:
“For most of us, our risk of dementia depends on the complex interaction of our age, genetics and lifestyle. We know that visual impairments such as macular degeneration and cataracts have been linked to a higher risk of dementia, but there is little research looking at cataract surgery and its effect on dementia risk.

“From this study we do not know why people who had cataract surgery had a roughly 30% lower risk of developing dementia. Although the researchers attempted to control for other factors that could affect a person’s risk, it’s not possible to draw firm conclusions about how cataract surgery could cause this lower risk of dementia, or how cataracts could potentially contribute to dementia either.

“Participants in this study were mainly white British, which is not representative of the entire population. Future research will need to include participants of a range of ages and ethnicities to fully explore any potential link between eye conditions, surgeries and the risk of developing dementia.

“The findings from this study show the need for more research focusing on the connections between the eyes and the brain, and how different eye conditions can affect dementia risk.”

You can read the full paper ‘Cataract surgery associated with a lower risk of developing dementia’ in JAMA Internal Medicine.

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