Research has found that the eyes can reveal early signs of cognitive decline, with those who perform worse on simple vision tests having a higher risk of developing dementia over a decade later, according to two large population studies in the UK and Australia. The UK study found that participants with slower visual processing speeds were more likely to develop dementia over the following 12 years, while the Australian study found deteriorating visual acuity was a significant predictor of cognitive declines over a similar 12-year period. The findings suggest that identifying these changes early and addressing them may reduce the risk of Alzheimer's disease. The Lancet's latest Commission on dementia in 2024 identified vision loss as a new risk factor for cognitive decline. However, despite these findings, the tests were not able to identify which individuals would be diagnosed with dementia based on their vision scores alone. The researchers suggest that such tests could be integrated into the screening process for dementia risk alongside other cognitive tests.