April 21, 2024

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Cataract surgery will reduce the risk of dementia nearly 30%?

Cataract surgery will reduce the risk of dementia nearly 30%?


Cataract surgery will reduce the risk of dementia nearly 30%? 

Is vision related to dementia? New research found: 30% lower risk after cataract surgery!


Dementia affects nearly 50 million people worldwide, and there is currently no therapy that can effectively change the course of the disease.

Research suggests that visual impairment may be an important risk factor for dementia, and cataracts affect most elderly people at risk of dementia.


Cataracts are the leading cause of blindness worldwide, affecting more than 35 million people worldwide and causing approximately 20 million people to lose sight.

Visual function is so important to the elderly. Will interventions to preserve vision, such as cataract surgery, change the risk of dementia?


A recent study published in JAMA Internal Medicine pointed out that cataract surgery is associated with a nearly 30% reduction in the risk of dementia.


Cataract surgery will reduce the risk of dementia nearly 30%?

Screenshot source: JAMA Internal Medicine


This observational study included a total of 3,038 participants with an average age of 74.4 years.

These participants were diagnosed with cataracts or glaucoma, but did not suffer from dementia. The researchers followed up every 2 years until the patient developed dementia.


The researcher evaluated the cognitive ability of the participants according to the cognitive ability screening, and the score range was 0-100 points.

Participants with scores below 85 received further neurological tests. The main outcome is the occurrence of dementia as defined in the “Diagnostic and Statistical Manual of Mental Disorders” (Fourth Edition).


After an average follow-up of 7.8 years, it was found that 853 participants developed dementia, of which 709 had Alzheimer’s disease, and about half of the participants (45%) had undergone cataract surgery.


After adjusting for years of education, smoking history, and stratifying according to APOE e genotype (Alzheimer’s disease risk-related gene), gender, and age at the time of cataract diagnosis.

Researchers found that compared with participants who did not undergo cataract surgery, any participant who had undergone surgery on one eye had a 30% lower risk of developing dementia for any reason for at least 10 years after surgery (RR=0.71, P<0.001).


After adjusting for multiple potential confounding factors (such as eye surgery within two years before the diagnosis of dementia, etc.), the researchers still found similar results. And cataract surgery is also related to reducing the risk of Alzheimer’s disease.


However, compared with cataract surgery, receiving glaucoma surgery (which cannot restore vision) is not significantly associated with the risk of dementia.


In addition, the researchers also found that when considering the relationship between cataract surgery, education level, smoking history, gender, and APOE genotype and the risk of dementia, the only factor that is more protective than cataract surgery is not carrying APOE e4 allele (Alzheimer’s disease high-risk gene).


Dr. Cecilia SLee, the first author of the study and associate professor of ophthalmology at the University of Washington School of Medicine, said: “The study adjusted for some confounding factors and still found that cataract surgery is strongly associated with the risk of dementia.”


Researchers analyzed the mechanism of cataract surgery and reduced risk of dementia. First, after cataract surgery, people may receive higher-quality sensory input, which may be beneficial in reducing the risk of dementia.

Secondly, cataract surgery can reactivate the cells that sense blue light. While people get more blue light, it may also help regulate the sleep cycle and cognitive function.

Finally, visual impairment may lead to psychosocial difficulties, withdrawal of social interaction, and decreased activity or exercise, all of which may be related to cognitive decline.


The research team said that the study also has limitations. For example, only the first cataract surgery of the participants was evaluated, so it is uncertain whether subsequent surgery will affect the risk of dementia.


The paper summarized and pointed out: The results of the study show that there is a significant correlation between cataract surgery and the lower risk of dementia in adults ≥65 years of age.

This result is of great significance to the care of the elderly, and to a large extent, it may improve the quality of life of individuals and their families.

The results also provide strong evidence, insights and potential treatments for further research on the relationship between dementia and other retinal diseases (such as age-related macular degeneration) to slow or prevent age-related dementia.




[1] Lee, CS, et al. (2021). Association Between Cataract Extraction and Development of Dementia. JAMA Internal Medicine, DOI: 10.1001/jamainternmed.2021.6990

[2] Study: Cataract surgery linked with lessened dementia risk. Retrieved 6-DEC-2021, FROM https://www.eurekalert.org/news-releases/936609

Cataract surgery will reduce the risk of dementia nearly 30%?

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