Turns out, two of the most dreaded health issues associated with aging - eye problems and dementia, commonly coexist. Recent medical studies suggest many dementia cases were preventable with better eye care. Learn more about these studies and eyesight problems linked to dementia in our article.
Link Between Vision and Dementia
A thorough study conducted by the Kellogg Eye Center at Michigan Medicine found older adults with vision issues, including those who weren’t able to see well even when wearing their usual eyeglasses or contact lenses, had a higher risk of dementia. The study, which included nearly 3,000 older adults over the age of 71, found that:
Nearly 22% of people with impaired vision for seeing up close, had dementia
33% of those with moderate or severe distance vision impairment and blindness, had signs of dementia
26% of those who had trouble seeing letters that didn’t contrast strongly against a background had dementia
After adjusting for other differences in health status and personal characteristics, people with moderate to severe distance vision issues were 72% more likely than those with no vision issues to have dementia.
Neurodegenerative Processes
The defining characteristic of dementia is progressive degeneration of brain cells, responsible for cognitive decline and functional impairment. Interestingly enough, similar neurodegenerative processes may also manifest in the eyes. Proteins like amyloid-beta, tau, and alpha-synuclein, commonly associated with Alzheimer's, have been found in the retina and optic nerve of patients with dementia.
Moreover, the retinal nerve fiber layer thickness, a measure of retinal ganglion cell density, correlates with cognitive function in individuals both with and without dementia. This indicates a possible correlation between neurodegenerative changes in the brain and those in the retina.
Vascular Factors
Vascular damage is another common occurrence in some eye diseases and dementia. Hypertension, diabetes, and atherosclerosis can compromise blood flow to the eyes and the brain. In the context of dementia, poor cerebral blood flow relates to cognitive decline.
Similarly, an inadequate blood flow to the eyes results in retinal vascular occlusion, ischemic optic neuropathy, and diabetic retinopathy, all of which may cause visual impairment. The shared vascular risk factors emphasize the need for managing hypertension and diabetes.
Shared Risk Factors
Beyond biological processes, eye problems and dementia share predisposing risk factors:
Advancing age
Genetic predisposition
Lifestyle factors
Aging is the most significant risk factor for dementia, cataracts, glaucoma, and age-related macular degeneration. As for genetic predisposition, some genetic variants are present in both dementia and certain forms of glaucoma. Smoking, sedentary behavior, and poor diet also contribute to eye problems and cognitive decline.
Potential Impact of Better Eye Care
The National Institute on Aging (NIA) suggests up to 100,000 U.S. dementia diagnoses might have been prevented. Correcting vision problems through eye exams, eyeglasses, and cataract surgery could be one of the top preventive actions to reduce the risk for Alzheimer’s and related dementias.
According to projections, there will be about 250,000 dementia diagnoses in the United States by 2050, caused by visual problems. This highlights the need for further research to explore the link between eye problems and dementia. And to test if addressing correctable vision problems is an effective intervention to protect cognitive health.
Until recent years, there was not much research on the matter. So right now, there is not enough public awareness about eyesight problems linked to dementia. Yet, more awareness may encourage people to seek help for their vision difficulties, potentially preventing or delaying the onset of dementia.
Eye Problems Linked to Dementia
While the abovementioned studies associate these eye conditions with an higher risk of dementia, they do NOT necessarily cause dementia:
Age-related macular degeneration (AMD)
Diabetic-related eye diseases
Cataracts
Glaucoma
More scientific research is necessary to understand the exact link between these eye conditions and dementia.
RELATED: Eye Risks When You Have Diabetes
The Role of Healthcare Providers
Healthcare providers and practitioners play a crucial role in the context of eyesight problems linked to dementia. Medical staff should educate patients about the potential link between vision and dementia, encouraging them to be more proactive about eye care.
As the understanding of the connection continues to grow, one thing is clear - addressing vision problems is pivotal to promoting cognitive health. Regular eye exams are a sure way to detect eye disorders early and provide treatment on time.
Checked by Atanas Bogoev, MD.