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Rising temperatures linked to vision impairment

As Earth grows warmer due to climate change, the potential health effects on the human population are becoming more visible and concerning. One such emerging health risk seems to be a marked increase in serious vision impairment, particularly among older adults, living in warmer regions of the United States.

A comprehensive study involving 1.7 million people has provided strong evidence for this alarming correlation. The study reveals that older adults living in regions with average temperatures of 60 degrees Fahrenheit or higher, which is comparable to the warm climate of South Florida, are significantly more likely to suffer from blindness or difficulties in seeing, even with glasses.

“The link between vision impairment and average county temperature is very worrying if future research determines that the association is causal,” explained Esme Fuller-Thomson, the co-author of the study and director of the University of Toronto’s Institute of Life Course and Aging

This concern is intensified in the light of climate change predictions that project a rise in global temperatures. “It will be important to monitor if the prevalence of vision impairment among older adults increases in the future,” said Fuller-Thomson.

The research uncovered a disturbing trend: compared to residents of counties with average temperatures less than 50 degrees F, the odds of severe vision impairment rose in tandem with temperature increases. 

The likelihood was 14 percent higher for residents of counties with temperatures ranging from 50-54.99 degrees, and 24% higher in places where average temperatures fell between 55-59.99 degrees. For those living in regions with even warmer climates, the odds of vision loss were a staggering 44% higher.

Remarkably, the link between higher temperatures and vision impairment remained strong even when demographic factors like age, sex, and income were taken into consideration. 

“It was powerful to see that the link between vision impairment and temperature was consistent across so many demographic factors including income,” said study co-author Elysia Fuller-Thomson, a graduate student at the University of Toronto.

The researchers found this correlation was stronger among individuals aged 65 to 79 compared to those aged 80 and above. The link was also found to be more prevalent among men than women. However, the exact reason why temperature has such an impact remains an enigma.

Underlying causes

The team proposed potential causes for this correlation, such as increased ultraviolet light exposure, air pollution, infections, and degradation of folic acid with rising temperatures. 

The consequences of this development are alarming, considering that vision problems are a significant cause of disabilities and functional limitations. They contribute to falls and deteriorate the quality of life among older adults.

The research was focused on data from six consecutive waves of the American Community Survey, targeting Americans aged 65 and above. Average temperature data was obtained from the National Oceanic and Atmospheric Administration and combined with the survey data to draw these conclusions.

These critical findings have been recently published in the journal Ophthalmic Epidemiology, pointing to an urgent need for further investigation into the links between climate change and health.

More about vision impairment 

Vision impairment refers to a decrease in the ability to see to a certain degree that can’t be corrected fully with eyeglasses, contact lenses, or eye surgery. It is often characterized by partial or complete loss of sight or inability to see clearly.

Various types 

Low vision

This is a significant reduction of visual function that cannot be fully corrected by glasses or contact lenses. People with low vision may have difficulty performing everyday tasks like reading, recognizing faces, or crossing the street.

In the U.S., this is defined as vision that’s 20/200 or worse in the better seeing eye with the best possible correction, or a field of vision that is 20 degrees or less.

Color blindness

This is the inability to see colors in a normal way. The most common type is red-green color blindness, but there are many variations and degrees of color blindness.

Night blindness

People with night blindness (nyctalopia) have difficulty seeing in low light conditions or at night.


This is the complete lack of vision. Blindness can be due to genetic mutations, injuries, diseases, or age-related conditions.


Causes of vision impairment include eye diseases like macular degeneration, glaucoma, and cataracts; systemic diseases like diabetes; and injuries or accidents. Sometimes, vision impairment can be present from birth.


Treatments for vision impairment can include glasses, contact lenses, visual aids, vision rehabilitation, and surgery, depending on the type and cause of vision impairment. 

However, some forms of vision impairment cannot be reversed. In such cases, resources and training can help individuals to adapt to their vision loss and maintain a high quality of life.


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