Objectively Measured Visual Impairment and Dementia Prevalence in Older Adults in the US
A 2021 study from the National Health and Aging Trends Study aimed to investigate the link between objectively measured visual impairment (VI) and dementia in older adults in the United States. The study found that all types of VI, including distance VI, near VI, and contrast sensitivity impairment, were associated with a higher prevalence of dementia among older individuals. Having multiple types of VI had an even stronger connection with dementia than having a single type of VI. The study used updated data from 2021, employing tablet-based tests for assessing visual function, and defined dementia through cognitive tests, screening interview scores, or medical diagnoses. Dementia prevalence was notably higher in individuals with near VI, distance VI (ranging from mild to severe), and contrast sensitivity impairment compared to those without these visual impairments. This research highlights the importance of prioritizing vision health, especially among older adults, as most VI is preventable or treatable with interventions such as glasses or cataract surgery. It suggests that optimizing vision may help preserve cognitive function and reduce dementia risk, potentially warranting further investigation through randomized trials.