Cataract surgery associated with lower risk of dementia

A large longitudinal study has found evidence that having cataract surgery may reduce the risk of developing dementia, the National Institute on Aging (NIA) announced.

Restoring the patient’s sight may be behind the reduction, the researchers theorize; previous studies have shown a link between sensory loss – for example becoming deaf or blind – and dementia.

Vision loss, in particular, has been linked to dementia risk, in part because of the social isolation it can cause, as well as the difficulty it presents in obtaining mental stimulation, The Washington Post reported.

Subjects who underwent cataract surgery had a 30% reduction in the risk of dementia.

Restoring some of the vision lost through cataract surgery can therefore help prevent dementia disorders from taking hold or accelerating.

If the results are confirmed, it could help change the way doctors and patients tackle dementia, said Nathaniel A. Chin, assistant professor of medicine at the University of Wisconsin who was not involved in the the study. New York Times.

“We can talk to people about the potential improvements in brain health from cataract surgery as well as the need to address vision across the lifespan as a way to protect cognition,” Chin said.

Brain burden: According to the NIA, dementia affects nearly 50 million people worldwide. Dementia can take various forms – including Alzheimer’s disease, frontotemporal dementia and dementia with Lewy bodies – and has proven to be frustrating and resistant to treatment.

And even when a drug is approved, like aducanumab to treat the plaques associated with Alzheimer’s disease, it may be based on a theory that we’re not entirely sure is correct – for example, that a protein called amyloid in the brain causes Alzheimer’s disease.

As more people live longer, cases of dementia are likely to rise, as the disease is “strongly associated with aging”, the NIA said.

The same goes for sensory loss, such as loss of vision due to cataracts.

The researchers analyzed thousands of participants and decades of data.

Clear Clouds: Cataracts are caused by a clouding of the lens of the eye; in severe cases, they make the eyes milky. Cataracts can cause many vision difficulties, including blurred/clouded vision, night blindness, and color fading.

According to the Post, the only cure is cataract surgery, where the clouded lens is removed and then replaced with a prosthetic lens that restores vision. It is this restoration of vision, according to the researchers, that could be the key to reducing the risk of dementia.

Risk reduction: In their study published in JAMA internal medicineresearchers analyzed patient data in a large study called Adult Changes in Thought, which has been tracking the health of Kaiser Permanente Washington patients for decades.

The researchers looked at 3,038 patients whose data was collected between 1994 and 2018. The patients were all aged 65 or older, did not have dementia at the start of the study, and all were diagnosed with cataracts or glaucoma before being diagnosed with dementia.

The 1,382 patients who underwent cataract surgery showed an almost 30% reduction in the risk of developing dementia compared to patients who did not have cataract surgery.

“We were stunned by the magnitude of the effect,” study author Cecilia S. Lee of the University of Washington told the NYT.

Restoring the patient’s sight may be the cause of the reduction; previous studies have shown a link between sensory loss and dementia.

The study controlled for a number of different factors, including age and other health issues between the two groups.

Importantly, they addressed concerns that people who chose to have eye surgery were likely to be healthier than those who didn’t, and were therefore already less likely to develop dementia for longer. other reasons.

To help control this, researchers compared cataract surgery patients with patients who had glaucoma surgery, which does not restore vision, and found no reduction in dementia risk for glaucoma surgery patients. .

This “supports the idea that it is not just about eye surgery or being healthy enough to undergo surgery, but rather that the effect is specific to cataract surgery”, said Lee.

More answers needed: Although the research is promising and agrees with previous studies linking the loss of our senses to the onset of dementia, it is not, as is often the case in the world of research on dementia and the brain, from an open and closed case.

Exactly how cataract surgery can reduce the risk of dementia remains unknown. And because the study only looked at patients from their first cataract surgery, it’s unclear if a second cataract surgery in their other eye had an impact on dementia risk, he said. the NIA.

If further research confirms these findings, cataract surgery may have clinical relevance for patients at risk of dementia.

Additionally, since more than 90% of patients in the follow-up study self-identified as Caucasian, the results may not translate to other patient populations; the Adult Changes in Thought study is currently attempting to recruit a more diverse population.

If further research supports these findings, “cataract surgery may have clinical relevance in older adults at risk of developing dementia,” the authors write.

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