Researchers have warned ageing populations could fuel a marked increase in dementia rates in coming years. Fear of the disease looms large in the minds of many because it robs sufferers of their independence. Identifying the risk factors, however, has proven helpful in tackling sky-high rates. According to various bodies of research, having certain eye conditions could predispose people to neuro-degeneration. The risk, however, may be even greater in individuals with other chronic health issues.
Data published in the British Journal of Ophthalmology in 2021 linked the incidence of three different ocular conditions to an increased risk for dementia.
According to the study, age-related macular degeneration (AMD), cataracts, and diabetes-related eye disease (DRED) may all be independently associated with a risk of cognitive decline.
The study of more than 112,000 adults enrolled in the UK Biobank study, found the risk for dementia to be 26 percent higher among patients with AMD, 11 percent higher among people with cataracts, and 61 percent higher among those with DRED.
People who suffered from two ophthalmic and two systemic conditions were at an even greater risk of dementia than those with just one of either.
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In fact, the findings showed people with at least two ophthalmic and at least two systemic conditions were almost three times more likely to develop dementia, according to the study authors.
While an ophthalmic condition usually affects the eyes, a systemic condition typically affects the entire body, rather than a single organ.
Medlineplus offers the example of high blood pressure as a systemic disorder or the flu as a systemic disease.
The study’s author, Xianwen Shang, told Medscape Medical News: “Our findings suggest that it may be better to do screening among middle-aged or older adults, with one or more [conditions] of obesity, hypertension, diabetes, cardiovascular disease or depression.”
In previous research, the risk of dementia appeared to be higher among people diagnosed with the conditions at a younger age.
This suggests the provision of prior health records could aid health practitioners in assessing a patient’s dementia risk.
Shang added: “Thus, information on the age at diagnosis of an ophthalmic condition and the importance of systemic conditions would be useful for detection or prediction of dementia.”
There is mixed evidence, however, confirming whether or not treatment of the condition can reduce the risk of dementia.
A study published in the JAMA Internal Medicine last year made a strong case that removing cataracts could reduce the risk of developing dementia.
The researchers drew their conclusion from a study of the relationship between cataract surgery and dementia risk in more than 3,000 adults, none of whom had dementia at the start of the study.
Why may eye problems cause dementia?
Neurodegenerative diseases cause a number of changes in the brain, including the function of the eyes.
When patients experience visual difficulties it is because the disease has affected part of the brain that handles visual information.
The British Medical Journal explains that vision impairment can “reduce stimulation of visual sensory pathways”, which may accelerate the progression of dementia.
The same risk exists for older adults who start losing their hearing, as this usually indicates underlying issues in the blood system.
Alzheimer’s Research UK explains: “Certain types of dementia, particularly vascular dementia, are caused when there is less blood flow reaching the brain. This can damage our brain cells.”
While some risk factors for dementia are unmodifiable, there is substantial evidence that eating healthily and exercising regularly will stand the brain in good stead.