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Study shows cataract surgery reduces risk of dementia by up to 30%

Study shows cataract surgery reduces risk of dementia by up to 30%

Wednesday 09 March 2022

Developing a disease of the brain is among the greatest fears a person can have. Approximately 50 million people have a dementia diagnosis currently, and an effective treatment for the condition has not been developed yet. Naturally, research discussing this topic affects all of us, and we have some positive research to discuss.

A recent report published by JAMA Internal Medicine, has shown that patients who have undergone cataract surgery are 30% less likely to develop dementia, up to ten years after the surgery.

This was the culmination of a huge, long-term study started in 1994 with over 3,000 individuals. Thousands of follow-up consultations, as well as over 25 years of data were analyzed, in what is one of the more significant sensory-dementia studies we have seen at this point.

Sensory input upon the brain is a crucial part to maintaining its health. It is well known at this point that maintaining an “active” brain can delay the onset of the debilitating condition. It serves to reason then, that ensuring sensory information is as accessible as possible will keep the visual cortex stimulated and healthy.

The blurring of our vision by cataracts affects stimulation of the brain in two ways. Firstly, they reduce our general ability to see, and when you can no longer trust your eyes, your willingness to be independent will decrease drastically. This can lead patients into sedentary, wary lifestyles which avoid risk and reduce access to new sensory stimuli. As stated in the study:

“Cataract-related visual impairment may decrease neuronal input, potentially accelerating neurodegeneration or magnifying the effect of neurodegeneration through cortical atrophy. The visual cortex undergoes structural changes with vision loss.”

Not only can reduced vision loss lead to neurodegeneration, but cataracts also appear to filter the blue part of the visible-light spectrum to a higher degree - affecting the body’s circadian rhythm. While too much blue light can affect your circadian rhythm negatively preventing sleep, conversely if you are not receiving enough, your retina will not respond to normal stimuli to keep your mind awake to as high a degree as it should. If you aren’t able to wake up properly on a consistent basis, you can quickly devolve into a state of near-perpetual tiredness.

Cataract surgery in the 21st century has become one of the most well-developed processes within ophthalmology, with surgery often completed in less than one hour at a high rate of success. When asked about the significance of these results, Cecilia S Lee, leader of the study, has stated that:

“This kind of 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 lessening dementia risk in older individuals.”

Of course, as with studies of any nature, corroborating evidence from larger projects will be the crucial development. However, the more than 25 years of data examined in this study have provided a sturdy backbone for related projects in future.

This study could well prove to be the first in a series of protective measures which reduce the risk of dementia for all of us in the future.


Lee CS, Gibbons LE, Lee AY, et al. Association Between Cataract Extraction and Development of Dementia. JAMA Intern Med. 2022;182(2):134–141. doi:10.1001/jamainternmed.2021.6990

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