Correcting Vision May Prevent or Delay Dementia

About 50 million people around the world today live with dementia—a number projected to triple by 2050.

Without effective dementia medications, leaders in the field are looking to prevent or slow its onset by addressing lifestyle and public health risk factors that we can change.

In the 2020 update to their landmark 2017 report, the Lancet Commission on Dementia Prevention, Intervention and Care listed a dozen modifiable risk factors for dementia: low education levels, hearing loss, hypertension, obesity, smoking, depression, social isolation, physical inactivity, diabetes, air pollution, alcohol use and traumatic brain injury. The commission estimates that overcoming these risk factors could prevent or delay four in ten dementia cases worldwide.

Compelling new research from a team led by Kellogg’s Joshua Ehrlich, M.D., M.P.H., indicates a critical risk factor is missing from that list: visual impairment. The study, published in JAMA Neurology in April, finds that an estimated 1.8 percent of U.S. dementia cases—more than 100,000 cases—may have been prevented by maintaining healthy vision.

“Most people with dementia don’t have vision impairment, and most people with vision impairment won’t develop dementia,” Dr. Ehrlich clarifies. “But this study indicates that, on average, those with vision impairment do seem to face higher dementia risk.”

The next step is to confirm the study’s findings with evidence from interventional studies. Dr. Ehrlich is part of a team developing a randomized clinical trial to evaluate the impact of vision correction on slowing cognitive decline. The CLEVER study (Cognitive Level Enhancement Through Vision Exams and Refraction) is expected to launch in India in the next year.

Dr. Ehrlich stresses that additional research is needed to determine whether a reduction in the incidence of dementia could be achieved through relatively economical, accessible interventions like eye exams, glasses and cataract surgeries.