Vision loss makes list of 14 risk factors for dementia

Count vision loss among two fresh risk factors identified by a respected Lancet Commission on dementia prevention, intervention and care, based on “new, helpful evidence.” 

The commission last issued a list of risk factors for dementia in 2020. Reducing those risk factors may prevent or delay “nearly half of dementia cases,” say the authors of the update, “Dementia prevention, intervention, and care: 2024 report of the Lancet standing Commission,” released in late July in The Lancet. 

“Be ambitious about prevention,” the authors urge. “Prevention involves both policy changes at national and international governmental levels and individually tailored interventions.” 

Jacqueline Theis, O.D., shines a spotlight on the role of optometry in the care of patients with dementia. Dr. Theis adds: “The addition of vision loss to the risks list significant: There are many things that we can do in our eye exam to help promote modifying these risk factors.” 

Other factors include high cholesterol (also new to the list), less education, head injury, physical inactivity, smoking, excessive alcohol consumption, hypertension, obesity, diabetes, hearing loss, depression, infrequent social contact and air pollution. 

The Lancet article provided estimates that worldwide 157 million people will have dementia by 2050, compared to 57 million in 2019. The prevalence of dementia was greater in lower-income countries compared to higher income countries. The commission advocates for a greater emphasis on “multicomponent interventions,” through public policy and care. 

The study’s authors note that the longer patients are exposed to a risk factor the “greater effect.” 

As we live longer, study gives hope

The addition of untreated vision loss to the list of 14 risk factors is “highly significant” for doctors of optometry, “because the article emphasizes an often-overlooked area of preventative health—vision loss,” says Dr. Theis, who practices at Virginia Neuro-Optometry, part of the multidisciplinary Concussion Care Centre of Virginia. 

She adds: “Eye care (optometry/ophthalmology) is an integral part of the health care team, and beyond correcting vision, the ocular health examination can reveal other systemic and neurologic conditions such as diabetes, hypertension and high cholesterol the patient may be unaware they had. Part of being a teammate is ensuring the patient sees the other health care team members and are taking their prescribed medications as indicated. Making sure that the patient sees their primary care physician regularly, gets their blood sugar and cholesterol checked and reinforcing other providers recommendations to participate in exercise and maintain a healthy and nutritious lifestyle can all help prevent risk factors for dementia.” 

 There is an increasing interest in modifying risk factors to prevent and slow dementia. 

“The article gives some hope,” Dr. Theis says. “This is important on a public health level because as people live longer, the number of people who live with dementia will continue to rise.” 

Eye doctors can further help by identifying and implementing prevention strategies, such as screening for and referring for cessation counseling for smoking/alcohol abuse, making sure patients are seeing their primary care physician, checking blood pressure at routine examinations, and encouraging patients to exercise or wear helmets during appropriate sporting activities to promote eye and brain health. 

Meta-analysis data showing that untreated vision loss is a modifiable risk factor for dementia, Dr. Theis says. And that signals to non-eyecare physicians “how important it is to refer for annual comprehensive eye exams, particularly in patients at high risk for dementia and as patients age.” 

Prioritizing policy and health care 

The update made several recommendations for policymakers, doctors and patients. Among them:

• Ensure good quality education is available for all and encourage cognitively stimulating activities in midlife to protect cognition.
• Make hearing aids accessible for people with hearing loss and decrease harmful noise exposure.
• Treat depression effectively.
• Encourage use of helmets and head protection in contact sports and on bicycles.
• Encourage exercise because people who participate in sport and exercise.
• Reduce cigarette smoking through education and price control. Prevent smoking in public places.
• Prevent or reduce hypertension and maintain systolic blood pressure of 130 mm Hg or less from age 40 years.
• Maintain a healthy weight and treat obesity as early as possible, which also helps to prevent diabetes.
• Prioritize age-friendly and supportive community environments and housing and reduce social isolation by facilitating participation in activities.
• Make screening and treatment for vision loss accessible for all.
• Reduce exposure to air pollution. 

“Considerations for people with dementia interventions after diagnosis help people to live well with dementia, including planning for the future,” the authors say. 

Educating and motivating—what optometrists can do 

Doctors of optometry have long recognized that the eyes are “amazing biomarkers for systemic and neurologic health,” Dr. Theis says. “By viewing the eye externally and internally, optometrists can visualize blood flow and document vascular changes as a proxy for cardiovascular health,” she says. We can use an OCT to measure the structure of the retina/optic nerve, which are extensions of the central nervous system, and by quantifying eye motion, we have the ability to measure cerebral/neurologic function.” 

Further, optometrists provide comprehensive eye exams that can detect not only eye conditions but systemic conditions such as diabetes. They can screen for depression and refer patients to physicians and therapists; encourage patients to wear eye and head protection, Dr. Theis says. 

The Lancet update underscores the importance of optometrists and ophthalmologists maximizing the visual acuity of patients of all ages, Dr. Theis says. 

Eye doctors have a role in: 

Educating care providers, patients and policymakers. 

Says Dr. Theis: “You need vision to participate in the world—to read, to drive, to exercise. When you look at the list of modifiable risk factors such as exercising, participating in social events, and participating in cognitively stimulating activities, not being able to see can be a barrier to those things. Additionally, many of the other risk factors such as smoking, increased alcohol, cardiovascular disease, diabetes and obesity are causes of vision loss—so it is cyclical in that the more we educate patients on the importance of their eyes and overall health at all ages, the better they can see and preserve their vision which will enable them to continue living the life they enjoy, which reduces dementia risk.” 

Motivating patients 

Says Dr. Theis: “People are terrified of going blind. While patients may not be motivated to quit smoking in isolation even though they know the health risks associated with it, they may be motivated to quit if they know that smoking increases their risk of blindness. And if we can get patients to recognize the importance of modifying risk factors such as smoking cessation, reduced alcohol intake, and exercising/nutrition for cardiovascular and metabolic health with the goal to prevent eye disease, we can indirectly also help prevent/modify neurologic disease as well.” 

How young is too young to look at the risk factors? Say the authors: risk factors should be tracked throughout life, though evidence suggests that midlife is a desirable time to start. 

“…it is never too early or too late to reduce dementia risk,” the authors say. 

Says Dr. Theis: “While it's known that factors such as genetics, lifestyle, and cardiovascular health affect dementia risk, the identification of childhood risk factors for permanently reduced vision like amblyopia, as well as untreated vision problems, adds new layers to our understanding. 

“This new evidence suggests a more integrated approach to prevention that includes vision care as part of dementia risk management. Early intervention could potentially mitigate this risk, emphasizing the importance of routine eye exams and treatment for visual problems throughout life."