With dementia affecting almost 6 million people in the US, it wouldn’t be unexpected that you may personally know of someone affected by dementia. The term dementia describes a group of conditions involving impaired cognitive abilities that interfere with daily tasks. The World Health Organization identifies dementia as a global public health priority due to its significant impact not only on the people experiencing dementia, but also on their surrounding communities. In the US, dementia costs the economy over $600 billion every year.
More About Dementia
There are several different types of dementia. The most well-known is probably Alzheimer’s Disease, which is also the most common form of dementia, accounting for 60-80% of all dementia cases. Other types of dementia include vascular dementia, fronto-temporal dementia, or dementia from reversible causes, such as certain medications or thyroid dysfunction.
Symptoms of dementia can include:
- Poor memory
- Difficulties with attention
- Defects in reasoning, judgment, and problem solving
- Difficulties with communication
Unfortunately, most forms of dementia have no cure. Though there are medications to manage some symptoms such as anxiety, or to try and slow the cognitive degeneration, more research is needed to understand and better manage these conditions.
Various risk factors for dementia have already been identified, including being older than 65 years of age, of African American heritage, or having a family history of dementia. In addition to these factors, studies have also suggested that reduced sensory input might increase the risk for dementia. This can include vision loss and hearing impairment, two conditions that increase in frequency with increasing age. With that said, enter the cataract surgeon.
What Are Cataracts?
Cataracts describe any opacity or haze of the lens inside the eye. Because this lens needs to be transparent for light to get through properly to the back of the eye, any clouding will result in a deterioration of your vision. This decline is not always noticeable, at least in the early days. Some people may not necessarily be bothered by the slight drop in their vision either.
Unlike dementia, cataracts are considered to be a normal part of aging, which has resulted in cataract surgery being the most commonly performed eye procedure around the world. Cataract surgery is typically considered once a person’s vision starts to hinder their daily tasks, such as reading comfortably or driving safely. Before this point, the effects of the cataract can be managed by updating your eyeglass prescription, improving your lighting while reading, or simply enlarging the text size on your digital devices.
How Can Cataract Surgery Help Dementia?
As has been previously mentioned, nothing can cure or reverse dementia (except for dementias induced by medications. However, researchers from the University of Washington recently published results demonstrating that cataract surgery was associated with a 30% lower risk of dementia.
The observational study collected data over a 24-year period in people aged 65 or older. Analysis of the data found that cataract surgery was significantly associated with a lower risk of developing dementia compared to people with cataracts who didn’t undergo surgery. This link persisted even after correcting for various other factors that could potentially muddy the results, including ethnicity, smoking history, gender, and age at the time of cataract diagnosis.
The researchers offered a few hypotheses to explain their findings. One is that having poor vision could lead to avoiding certain activities, including physical exercise or social interactions. It is already established that low levels of physical activity and withdrawal from social settings can increase the risk of cognitive deterioration. Another explanation is that the reduced input to the brain from having impaired vision can accelerate the degeneration of brain matter. Other studies have found that the brain’s gray matter in the visual cortex can increase in volume after a cataract operation. A third hypothesis is that trying to compensate for the reduced visual input may overload the brain and contribute to its deterioration.
Cataract surgery is able to restore and reverse any vision loss associated with the cataract. This isn’t to say that vision deficits from other causes, for example, macular degeneration, will be improved once the cataracts are removed. However, the improved vision from having the cataracts extracted may be sufficient (in some people) to mitigate their risk of slipping into dementia by counteracting the effects of all the hypotheses mentioned above. Removing the cataracts may also help to reduce dementia risk by allowing more blue light into the eye. Wavelengths at the blue end of the spectrum are known to activate certain cells in the eye, which can encourage activity in the cortex of the brain, helping to support cognitive function.
With dementia being in the top 10 leading causes of death among older people around the world, any way we can stop, slow, or avoid this disease is worth investigating.
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