December 28, 2022
As many as 100,000 cases of Alzheimer’s disease and other forms of dementia could have been better managed or even perhaps delayed with better eye care, according to a report funded by the National Institute on Aging. Identifying and correcting vision problems through such methods as regular eye exams, corrective eyeglasses or contact lenses, and cataract surgery could go a long way in helping to prevent or delay the onset of Alzheimer’s and related dementias, the findings suggest.
The study, published in JAMA Neurology, makes the case that poor vision should be added to a growing list of modifiable risk factors for dementia. Such risk factors include hearing loss, smoking, high blood pressure, obesity, diabetes, lack of exercise, lack of social contact, depression in later life, lack of education, head injuries, exposure to air pollution and excessive alcohol consumption. Together, these risk factors account for up to 40 percent of the cases of Alzheimer’s disease and other forms of dementia, experts say.
For the study, researchers analyzed data from the University of Michigan’s Health and Retirement Study, a long-running study that tracked more than 20,000 older Americans over many years. They calculated that about 1.8 percent of the dementia cases in the United States, or more than 100,000 cases of Alzheimer’s disease or other forms of dementia, could have been prevented or delayed with good vision care to improve vision. By 2050, that number could increase to more than 250,000, unless more effective treatments for Alzheimer’s disease are found.
The authors of the current study note that about 80 percent of vision impairment occurs in adults aged 50 and older, and that 90 percent of cases are preventable or have yet to be treated. One of the most common causes of blurry vision in older adults is cataracts, which cause gradual clouding of the normally clear lens of the eye.
Most cases of vision loss are treatable with two highly cost-effective interventions: eyeglasses (or contact lenses) and/or cataract surgery. Yet both of these corrective treatments remain underutilized in the United States, and around the world, especially among disadvantaged communities, the authors note.
Eye diseases like glaucoma, macular degeneration and diabetes-related retinopathy are also common in older people. Regular eye exams can help to identify these problems early, and effective treatments are available for many of these eye problems to limit vision loss.
Scientists note that poor vision may impair the brain in various ways. Poor vision, like poor hearing, is a form of sensory deprivation, in which the brain gets only limited stimulation. Stimulation of the brain, whether it’s through the senses or through cognitively stimulating activities like reading a magazine or newspaper, doing crossword puzzles, driving, or learning a new language, has been linked to a lower risk of dementia.
Poor vision, like poor hearing, also often results in social isolation. Older people who can’t see well may be reluctant to leave the house or drive to see friends; are more likely to reduce their participation in their previous daily routines and social activities; and are more likely to become depressed. Lack of social interactions and depression are likewise linked to a higher risk of developing dementia. Poor vision may also limit physical activity, which has been tied to better brain health.
It’s important to get regular vision checks every two years or so, and more often if you have a disease like diabetes or glaucoma. Getting good glasses or contact lenses (as well as hearing aids) to correct poor vision (or hearing) may be critical for helping to maintain good cognitive function, as well as to stay socially connected.
Regular vision checks are also important for those who already have Alzheimer’s disease. Earlier studies have shown that one in three nursing home residents with Alzheimer’s disease who need eyeglasses don’t have the right glasses and can’t see clearly. Poorly corrected vision may mean they are missing out on mentally stimulating activities that may help to ease aggravation and soothe symptoms of dementia.
Experts recommend that if you care for someone with Alzheimer’s disease, a few simple steps can help avoid vision-related problems. These include labeling eyeglasses with a person’s name and phone number so that if they are lost they can be more easily recovered; if possible having a spare pair of glasses on hand; and scheduling ahead of time regular eye exams to make sure vision prescriptions are up to date.
By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Marc Flajolet, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.
Source: Joshua R. Ehrlich, MD, MPH; Jenna Goldstein, BA; Bonnie K. Swenor, PhD, MPH; et al: “Addition of Vision Impairment to a Life-Course Model of Potentially Modifiable Dementia Risk Factors in the U.S.” JAMA Neurology, April 25, 2022