Cataract surgery, a well-established procedure for improving vision, may also offer cognitive benefits, according to recent research. A review published in the journal Ophthalmology revealed a 25% reduced risk of long-term cognitive decline associated with cataract surgery compared to not undergoing the procedure. Lead author Brian Sheng Yep Yeo and his colleagues from the National University of Singapore found this cognitive benefit across various outcomes, and the association held up in sensitivity analyses. Additionally, cataract surgery was linked to a 4% improvement in short-term cognitive test scores.
The review, comprising 24 articles with almost 560,000 participants, analyzed the potential cognitive benefits of cataract surgery. Similar studies on hearing aids and cochlear implants have also suggested cognitive advantages. A study in JAMA Neurology in December 2022 found that the use of hearing restorative devices was associated with a 19% decreased risk of long-term cognitive decline and a 3% improvement in short-term cognitive test scores.
A separate analysis conducted by Cecilia Lee and colleagues from the University of Washington, Seattle, using data from the Adult Changes in Thought study, indicated a 30% lower risk of dementia in individuals who underwent cataract extraction compared to those who did not. While these studies identify associations, the underlying reasons are yet to be definitively established.
Researchers propose several explanations for the observed cognitive benefits. Untreated cataracts may lead to visual impairment, resulting in cortical atrophy due to a lack of neuronal input. Visual deficits related to cataracts might impact perceptions, influencing cognitive abilities. Indirect effects, such as difficulty in social interactions and subsequent social isolation, could also contribute to cognitive deficits.
Some researchers speculate that visual impairment and cognitive deficits may share common causes, such as vascular changes affecting both the eye and the brain. A review on the bidirectional relationship between vision and cognition published in Ophthalmology even suggests a potential link between beta-amyloid deposits associated with Alzheimer’s and vision loss. While these findings highlight intriguing connections, further research is necessary to fully understand the mechanisms and implications of the observed associations.
