A population-based study led by public health researchers at the University of Miami Miller School of Medicine has revealed that visual impairment is associated with cognitive decline in aging adults.
The collaborative study, “Longitudinal Associations Between Visual Impairment and Cognitive Functioning,” was published in JAMA Ophthalmology, a journal of the American Medical Association, on June 28. Researchers analyzed the health data of more than 2,500 adults, aged 65 to 84, who were followed from about 1993 to 2001. The longitudinal investigation revealed that worsening vision in older adults has a strong association with cognitive decline but, conversely, cognition was not as impactful on vision.
“We found that the rate of worsening vision was associated with the rate of declining cognitive function, and that vision has a stronger influence on cognition than the other way around,” said the study’s lead author D. Diane Zheng, a Ph.D. candidate in the Miller School’s Department of Public Health Sciences.
The study was the first to document that vision is the dominating factor in the relationship between vision impairment and cognitive function, said Zheng.
As cognitive decline and visual impairment are common conditions that affect aging Americans, the research has implications for preventing or treating vision conditions as a means to protect against cognitive decline.
“The takeaway is that we need to pay more attention to preventing and treating vision loss to possibly reduce the rate of cognitive decline,” said study co-author David Lee, Ph.D., professor of public health sciences in the Division of Epidemiology and Population Health Sciences.
Byron L. Lam, M.D., an ophthalmologist at the Miller School’s Bascom Palmer Eye Institute, also collaborated on the study.
The sample population studied was from greater Salisbury, Md. The study subjects, who lived in local communities, were described as healthy and largely of Caucasian and black racial backgrounds. To measure visual acuity, researchers used the Early Treatment Diabetic Retinopathy Study charts, and cognitive status was assessed using the Mini-Mental State Examination.
Collaborating researchers at Johns Hopkins University collected data from the population during four different periods.
“The data collected by our colleagues in Salisbury offers snapshots of what’s happening among aging populations,” said Lee.
To further highlight the significance of the research, the investigators noted that the number of U.S. residents older than 65 — for whom worsening vision and declining cognitive function are common conditions — is projected to double in the next 40 years. Maintaining good cognitive ability is crucial for older adults to carry out day-to-day functions, and understanding the role that vision plays in cognitive changes could lead to ways to slow down the pace of cognitive decline and reduce age-related cognitive changes.