A population-based study led by public health researchers at the University of Miami Miller School of Medicine has revealed vision is the dominating factor in the relationship between vision impairment and a decline in cognitive function.

The collaborative study, Longitudinal associations between visual impairment and cognitive functioning, was published in JAMA Ophthalmology. Researchers analysed 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 Diane 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 public health sciences Professor David Lee.

To further highlight the significance of the research, the investigators noted that the number of US residents older than 65 - for whom worsening vision and declining cognitive function are common conditions - is projected to double in the next 40 years.