Did you know that researchers have linked the size of your temporalis muscle (responsible for opening your jaw) to your risk of dementia?

Yep ― the muscle’s volume can reveal how much age-related muscle loss called sarcopenia has taken place, which is itself linked to increased Alzheimer’s risk.

When strength loss is a sign of frailty, scientists think it might predict dementia risk nine years ahead of diagnosis.

But another physical change, which is easier for most of us to notice, has been associated with the condition over a decade before it’s clinically recognised.

In a TikTok video, health educator Dr Eric Berg explained that “the earliest sign of dementia involves the retina”.

Problems with night vision, central vision, and light sensitivity issues can all belie a higher risk, he claimed.

Indeed a 2024 paper from the University of Loughborough found that some vision changes have been associated with dementia 12 years before diagnosis.

The study, which looked at 8,623 participants from Norfolk who were dementia-free when the research began, followed individuals’ health over decades.

Participants were aged between 40 and 79 at the start of the study, which began in the ’90s ― but the data which scientists used for the eyesight and dementia links was collected between 2004 and 2011, when they were 48–92 years old.

In that period, participants took both cognitive and visual processing tests, including one which asked them to hit the space bar on a keyboard as soon as they saw a triangle.

By the end of the study, 537 people had been diagnosed with dementia.

Of those, the researchers found that people who had struggled more with visual processing 12 years before getting a diagnosis were more likely than those who had not struggled with it to develop the condition.

The Lancet says that keeping our eyesight healthy is one of the 14 “potentially modifiable” factors that can help us to prevent dementia, especially in older age.

Per Alzheimer’s Society: “Research shows that people with vision loss are about 50% more likely to develop dementia than people without vision loss.”

But not all eye changes seem to carry the same risk. For instance, cataracts and diabetic retinopathy have been associated with dementia; glaucoma and age-related macular degeneration have not.

It’s also hard to pin down exactly where correlation ends and causation begins. For instance, people with vision loss tend to be older (almost 80% are over 65) ― and we know age is the biggest risk factor for developing dementia.

Additionally, people with worse eyesight might socially isolate themselves, which can also increase dementia risk.

If you’re worried about your eyesight or signs of dementia, speak to your doctor as soon as possible, as both issues benefit from early diagnosis.