Cataract surgery linked with lessened dementia risk: Study

The mechanisms by which cataract surgery and lessened dementia risk are associated was not determined in this study. Researchers hypothesize that people may be getting higher quality sensory input after cataract surgery, which might have a beneficial effect in reducing the risk of dementia.

"These results are consistent with the notion that sensory input to the brain is important to brain health," said co-author Dr. Eric B. Larson, a principal investigator of the ACT study, and senior investigator at Kaiser Permanente Washington Health Research Institute.

Lee said another hypothesis is that after cataract surgery, people are getting 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," she said, "Cataracts specifically block blue light, and cataract surgery could reactivate those cells."

The study results highlight a strong case for further research on the eye-brain connection in dementia. Previous studies by Lee's group at the UW have shown a strong link between other retinal diseases, such as age-related macular degeneration, and the development of Alzheimer disease and dementia. Subjects with macular degeneration or other retinal degenerative diseases are more likely to develop dementia, In the current study, subjects undergoing vision-improving cataract surgery had lower risk of developing dementia. Further understanding the connection between the aging eye and brain may offer insights and potential therapies to slow or prevent age-related dementia.