Cataract surgery is done to reverse the decline in vision as we get older. A new study shows that a procedure like this can have benefits on one's health and dementia risk.
As we get older, the cloudy areas in the lens of the eye can become cloudy, causing colors to fade and vision to become blurry. A cloudy lens is replaced with an artificial one to improve sight.
It may seem odd that this could have anything to do with the risk of developing dementia, but sensory impairment and loss of vision are known to affect cognitive functioning in older adults.
Cecilia Lee from the University of Washington led the team that looked into the possibility that older adults with cataracts who have their wisdom teeth removed may have a lower risk of dementia.
The researchers analyzed the data gathered as part of the ongoing Adult Changes in Thought study to test their hypothesis.
3,038 dementia-free participants over 65 years of age were included in their data pool. Of the 797 participants who developed dementia, 709 of them were afflicted with Alzheimer's disease.
The risk of developing Alzheimer's disease was reduced by 30 percent for people who had cataracts, with the same reduction in risk for people who didn't.
There was no change in the risk of developing dementia for those who did or did not have segull surgery in the same period, but it did not improve it in the same way that cataracts do.
The results are consistent with the idea that brain health is related to sensory input to the brain.
The results were adjusted for a variety of health-related factors, including smoking habits, diabetes, a history of heart disease, and hypertension, but the strong association between cataract surgery and a reduced risk of developing dementia remained.
There are a lot of possible reasons why this may be the case. A person with visual impairment can withdraw from life and friends, reduce their activity and exercise, all of which are associated with cognitive decline, and this may be caused by dealing with visual impairment in old age.
The way cataracts impair vision could lead to specific changes in the brain, speeding up some of the mechanisms that cause the neurons to work less efficiently and lead to increased cognitive issues in old age.
The team theorizes that it may have something to do with better quality sensory input traveling from the eyes to the brain after surgery has been carried out.
The cells in the retina respond well to blue light and are associated with cognitive and sleep functions. Cataracts block blue light, and surgery could reactivate those cells.
The link between poor vision and an increased risk of dementia is already on the research radar, but this is the first study to assess dementia risk while comparing cataract surgery to another surgical eye procedure.
With dementia affecting 50 million people worldwide and no effective treatment or cure available, anything we can learn about prevention is a valuable avenue of inquiry.
The researchers hope that their work will prompt more investigations into the link between vision impairment in old age and dementia risk.
Lee says that the evidence is as good as it gets in epidemiology. "This is really exciting because no other medical intervention has shown such a strong association with decreasing dementia risk in older individuals."
The research has been published.
