A shared neurodegenerative pathway may link loss of contrast sensitivity and dementia. Glaucoma and Alzheimer’s disease both involve retinal neuron loss, for example. Interventions for improving contrast sensitivity may help patients. Click image to enlarge.

Cognitive decline and visual impairment pose significant threats to daily living and reduce quality of life, making these two health concerns—which are thought to be connected—crucial for study. Recently, researchers conducted a longitudinal study to investigate the association of worse baseline visual acuity and dementia likelihood. Their findings, published in American Journal of Ophthalmology, showed that visual acuity as well as contrast sensitivity were linked to incident dementia.

In the retrospective study, the researchers analyzed the data of 2,159 adults (mean age 77.9, 54% female participants, 88% white) from the 2021 and 2022 National Health and Aging Trends Study. Baseline median distance visual acuity was 0.08 logMAR (20/24), near visual acuity was 0.17 logMAR (20/29) and contrast sensitivity was 1.8 logCS. Over the follow-up period, 6.6% (192) of adults developed dementia.

The researchers reported that baseline distance and near vision and contrast sensitivity were associated with greater likelihood of incident dementia, and that change in contrast sensitivity but not visual acuity was associated with even greater likelihood of incident dementia.

“These findings suggest that visual function, especially contrast sensitivity, might be a risk factor for developing dementia,” the researchers wrote in their paper. “Contrast sensitivity change may also be a more sensitive indicator of dementia compared to visual acuity change, as shown with significant associations following a short follow-up duration (one year), and interventions targeted at preserving/improving contrast sensitivity may alter the risk of dementia.”