Older Adults in Hotter US Regions Face More Vision Problems, Study Suggests
A study led by researchers from the University of Toronto found that seniors living in warmer parts of the United States show higher rates of vision issues compared with peers in cooler, temperate climates. The findings emphasize how climate and local conditions may relate to eye health in later life.
Esme Fuller-Thomson and her team examined patterns across counties with different average temperatures. The analysis showed lower risk of age-related visual impairment in areas where mean temperatures stay below 10 degrees Celsius, such as Alaska. In contrast, regions with average temperatures from 10 to 12 degrees Celsius saw higher odds, and temperatures in the 12 to 15 degrees Celsius range were associated with even greater risk. Regions warmer than 15 degrees Celsius showed the highest levels of age-related visual impairment, with the increased risk reaching about 44 percent relative to the coolest areas.
The researchers caution that while a link between mean county temperature and visual impairment could be important, causality has not been established. With global temperatures expected to rise due to climate change, monitoring how the prevalence of vision problems among older adults may change becomes essential. The team notes that continued research is needed to confirm whether the temperature-vision link is direct or influenced by other factors.
The association between higher mean temperatures and more severe visual impairment held true across gender, income, and education levels of study participants. The effect was most pronounced in individuals aged 65 to 79 and somewhat less so in those over 80. Several explanations have been proposed to account for how heat could affect vision, including greater exposure to ultraviolet radiation, increased air pollution, infectious risks, and potential changes in nutrient processing such as folic acid with rising temperatures. However, none of these theories has been proven conclusively.
In a lighter, unrelated note, the text also references a historical debate among paleontologists about whether the ancient megalodon shark was warm-blooded, illustrating how scientific questions can span very different domains.