Age-related eye disease may be related to cognitive decline, but the exact relationship remains unexplained within the scientific literature. New research may be able to help, now finding that glaucoma patients scored lower on cognitive tests; the same relationship didn’t exist for AMD patients.

This cross-sectional, hospital-based study evaluated 336 adults aged 65 or older. A team measured cognition with six verbal cognitive tests, as well as activity level, visual acuity and visual fields.

The investigators found those with glaucoma or AMD were more likely to be older, female, have less education, have more depressive symptoms and were involved in fewer activities—overall, they had reduced life span.

As for cognition, patients with glaucoma scored lower on the digit span forward test, meaning they were able to recall 0.8 fewer digits than those with normal vision. The glaucoma group also scored lower on the digit span backward version and the logical memory test with immediate recall than participants with normal vision. The researchers noted that activity level mediated the relationship between glaucoma and the digit span forward test in a statistically significant way.

“We have found for the first time that glaucoma patients have worse scores on three cognitive tests that measure verbal memory and verbal working memory, while AMD was not associated with any of the cognitive outcomes,” the researchers wrote in the paper.

In an effort to brainstorm solutions to slow cognitive decline among those with ocular health problems, the team suggested cognitive training exercises could be developed that are geared toward people with vision loss.