Dementia is a growing public health problem that is placing unprecedented stress on healthcare systems, families, and marginalised communities across the globe. According to Alzheimer's Australia, by 2050, 730,000 Australians are expected to be diagnosed with dementia, which is why researchers are scurrying to find ways to prevent it and other memory loss-related conditions. Such proactive solutions are known as modifiable risk factors, and a new study suggests that vision impairment is one that warrants more attention.

The cross-sectional study, published in JAMA Neurology, analysed data which surveys a representative sample of approximately 20,000 people in America on ageing. Among 16,690 adults aged 50 and older, researchers found that an estimated 1.8% (more than 100,000) of dementia cases in the U.S. were associated with vision impairment.

How does vision impairment contribute to memory loss?

“A neural system maintains its function through stimulation from sensory organs,” neurologist Dr Julio C. Rojas. When vision stimulation is no longer present or impaired, “there will be a dying out of neurons, a rearrangement of the brain,” he added.

Another 2020 meta-analysis of 16 studies and over 70,000 patients published in Ageing and Mental Health also linked vision impairment with an increased risk of cognitive decline. It’s worth pointing out that vision loss also often goes hand in hand with the inability to confidently and comfortably socialise, which compounds dementia risk.

What does this mean for dementia prevention?

The good news is, according to the JAMA Neurology study, an estimated 90% of vision impairment is preventable or has yet to be treated. Plus, vision care is often cost-effective and underused, especially compared to the pricey intervention and long-term care dementia patients require. That means those 1.8% of dementia cases linked to vision loss could’ve potentially been avoided, and hopefully, in the future, they will be.