Caution Advised: Warm Climates Correlated with Serious Eye Conditions in Elderly U.S. Citizens

A new study indicates that Americans aged 65 and older living in hotter regions face an elevated risk of significant vision issues in comparison to their counterparts in more temperate zones. The underpinning cause of this correlation between higher temperatures and vision degradation remains undetermined, although theories include exposure to ultraviolet light, air contamination, and susceptibility to infections.

The research, which evaluated data from 1.7 million senior U.S. citizens, found that individuals in counties with an average temperature above 60°F experienced a markedly higher risk of substantial vision complications compared to those in cooler regions.

Published in the scientific journal Ophthalmic Epidemiology, the study asserts that American adults aged 65 and above who reside in warmer climates are more prone to experiencing severe visual impairments compared to those living in colder regions.

In counties where the average temperature ranged between 50 and 54.99°F, residents faced a 14% greater risk of substantial vision impairment when contrasted with individuals in counties where temperatures averaged below 50°F (< 10°C). This risk escalated to 24% for residents in counties with average temperatures ranging from 55 to 59.99°F and soared to 44% for those in regions with an average temperature of 60°F (15.5°C) or more.

Professor Esme Fuller-Thomson, the study’s lead author, expresses concern over the established link between vision issues and county average temperatures. “If subsequent research confirms this correlation as causative, it becomes troubling in the context of global warming. We will need to observe whether the incidence of vision impairment among older adults increases accordingly,” says Dr. Fuller-Thomson, who is also the director of the Institute of Life Course and Aging at the University of Toronto and holds a professorship in multiple faculties.

Co-author ZhiDi Deng, a recent pharmacy graduate from the University of Toronto, adds that vision impairments serve as a significant cause of disability and functional restrictions. “Significant vision problems can elevate the risk of accidents such as falls and fractures, adversely affecting the quality of life among the elderly. Addressing these vision-related issues also burdens the U.S. economy with tens of billions in annual expenses.”

Demographic Factors Do Not Alter Risk

Regardless of variables such as age, sex, income, and education, the relationship between average county temperature and the risk of severe vision impairment remained consistent.

“It was revealing to note that the temperature-vision impairment connection held across diverse demographic considerations, including economic factors,” says Elysia Fuller-Thomson, a graduate student at the University of Toronto and a co-author of the study.

The research found that the association was more pronounced for individuals between the ages of 65 and 79, males as opposed to females, and White Americans in comparison to Black Americans.

Unexplained Causality

Although the correlation between average county temperature and severe vision problems is compelling, the exact causative mechanisms are still unclear.

The authors of the study propose multiple possible explanations, including increased exposure to ultraviolet light, deteriorating air quality, infections, and the breakdown of folic acid due to higher temperatures. However, the study’s design does not offer conclusive evidence explaining how temperature impacts vision.

The data for this research were sourced from six consecutive annual surveys (2012-2017) of the American Community Survey, which included a nationally representative sample of Americans aged 65 and older. The study analyzed 1.7 million elderly adults who resided in the contiguous United States and were born in the same state. Average temperature data was collected from the National Oceanic and Atmospheric Administration and merged with data from the American Community Survey.

“Although we found a robust association between average county temperature and vision issues, these findings pose more questions than answers,” says Esme Fuller-Thomson. “Future research will explore whether temperature also correlates with other types of disabilities among older adults, including hearing issues and limitations in day-to-day activities.”

Reference: “Association Between Area Temperature and Severe Vision Impairment in a Nationally Representative Sample of Older Americans” by Esme Fuller-Thomson, ZhiDi Deng, and Elysia G. Fuller-Thomson, published on 20 June 2023 in Ophthalmic Epidemiology.
DOI: 10.1080/09286586.2023.2221727

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More about Vision impairment in warmer climates

• Association Between Area Temperature and Severe Vision Impairment Study in Ophthalmic Epidemiology
• American Community Survey
• National Oceanic and Atmospheric Administration
• Institute of Life Course and Aging, University of Toronto
• Factor-Inwentash Faculty of Social Work, University of Toronto
• Department of Family and Community Medicine, University of Toronto
• Climate Change and Health
• Impact of UV Light on Eyes
• Air Pollution and Eye Health