Routine retinal tests performed by opticians could help to identify those at risk of developing dementia, a new study reports. The scans – normally used to evaluate the integrity of retinal tissue and therefore eye health – offer up new insight as to the link between retinal deterioration and brain health.
A UK-led study featured a cohort of 32,000 people aged 40–69 years who underwent optical coherence tomography (OCT) of the retina, in particular the retinal nerve fibre layer (RNFL), as well as completing assessments for memory, reaction time and reasoning. Exclusion criteria included those with eye disease or vision loss, a history of ocular or neurological disease, or diabetes.
Researchers found that participants with the thinnest RNFLs were more likely to fail one or more of the tests and were twice as likely to have poorer follow-up assessments out to three years – pointing towards higher instances of cognitive decline.
The hypothesis behind the retinal testing method is that the deterioration of the retina could be reflective of changes occurring in the vasculature of the brain. Indeed, while deterioration of the retina in patients with established dementia has been known for some time, this new research points to probable dementia risk at a much earlier stage. This helps to build a case for clinical trials focusing on treatments that could be effective in slowing or even stopping dementia before it takes hold.
However, questions remain about the reliability of retinal thickness as a marker for dementia risk, with some experts arguing that many people with thin retinas will not go on to exhibit cognitive decline.
With this in mind, future emphasis might be better directed at ascertaining how OCT-based retinal tests fit in alongside other markers of dementia risk. “While a diagnosis of dementia will always rely on results from a number of different tests, further studies should look at how sensitive OCT could be at identifying those most at risk of cognitive decline in the general population,” commented Dr Laura Phipps from Alzheimer’s Research UK.
She added: “With future treatments for Alzheimer’s and other dementias likely to be most effective when given early in the disease process, research into sensitive and non-invasive early markers of disease is vital.”
BBC News. Optician’s eye test ‘could spot early dementia signs’. Available at: https://www.bbc.com/news/health-44936752.