Study: Cataract Surgery Lowers Dementia Risk


A prospective, longitudinal cohort study has found that cataract surgery is associated with a significant reduced risk of dementia. The study analyzed data from the Adult Changes in Thought (ACT) study, which included 5,000 people over the age of 65.(1)

Sensory impairment, such as vision or hearing loss, affects 20% of the population over the age of 65. Studies conducted in the past have shown an association between sensory impairment and cognitive decline. “Addressing sensory loss that affects a substantial portion of older adults may be a potentially modifiable risk factor of dementia in late life.”(1)

Study participants were cognitively normal and had been diagnosed with cataract when they enrolled in the study. Upon enrollment, and during biennial visits, participants had a physical exam and cognitive screening tests.(1) “Analysis for risk of developing dementia showed that subjects who had undergone cataract surgery in either eye were about 30% less likely to develop any form of dementia for at least 10 years after their surgery.”(2)

Researchers adjusted for an extensive list of health-related confounders, including smoking and years of education, and “healthy patient bias,” where participants who were healthier overall may be more likely to go ahead with cataract surgery than less healthy participants.

The study did not determine the mechanism by which cataract surgery affected dementia risk. Researchers hypothesize the removal of cataracts provides higher quality sensory input, which has a positive effect on brain health. Another hypothesis is that after cataract surgery people get more blue light. “Some special cells in the retina are associated with cognition and regulate sleep cycles and these cells respond well to blue light,” said Dr. Cecelia Lee, lead researcher. “Cataracts specifically block blue light, and cataract surgery could reactivate those cells.”(2)

An estimated 5 million Americans suffer from Alzheimer’s Disease or a related dementia, according to the Centers for Disease Control. The CDC forecasts this number will grow to 13.9 million people by the year 2060.(3)


(1) Lee, C. MD, Gibbons, L. PhD, et. al., Journal of The American Medical Association/Internal Medicine, Association Between Cataract Extraction and Development of Dementia,

(2) UW Medicine, Study: Cataract Surgery Linked with Lessened Dementia Risk,

(3) Centers for Disease Control, US Burden of Alzheimer’s Disease, Related Dementias to Double by 2060,

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