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Warmer temperatures directly linked to severe vision impairment in older adults

Older adults aged 65 years and up, who live in warmer temperatures, could be at greater risk of suffering from severe vision impairment. These older individuals had more vision problems than their counterparts residing in cooler climates.

This research was reported in a recent publication in the scientific journal Ophthalmic Epidemiology.

The scientists compared vision impairment across different temperature ranges. They found that older adults living in regions with an average temperature below 50°F had the lowest rates.

In comparison, there was a 14% increase in severe vision impairment for those in areas with an average temperature between 50-54.99°F.

This likelihood rose by 24% for older adults in regions averaging 55-59.99°F. It further increased by a significant 44% in areas where the average temperature was 60°F or above.

Results of the vision impairment study are deeply concerning

“The connection we’ve found between average county temperature and vision impairment is deeply concerning, especially if future research shows this association is causal,” says Professor Esme Fuller-Thomson, the lead author of the study.

Fuller-Thomson is the Director of the Institute of Life Course and Aging at the University of Toronto. She also teaches in the Department of Family and Community Medicine.

She added, “As global temperatures rise due to climate change, it’s crucial to see whether the prevalence of vision impairment among older adults also increases.”

Her co-author, ZhiDi Deng, is a recent pharmacy graduate from the University of Toronto. Deng emphasized that vision problems are a significant cause of disabilities and functional limitations among older adults.

“Serious vision impairment can lead to increased risk of falls and fractures, and negatively affect an older adult’s quality of life,” says Deng.

“The financial implications are also considerable, with vision impairments costing the US economy tens of billions each year. Therefore, the correlation between temperature and vision impairment is very worrying.”

Consistency of vision impairment across diverse groups

Interestingly, the team discovered that the relationship between average temperature and severe vision impairment was consistent across various demographic factors. These include age, sex, income, and education.

Elysia Fuller-Thomson, a graduate student at the University of Toronto, was struck by the strength of this correlation.

“It’s striking that the link between temperature and vision impairment remains steady across diverse income groups,” she observes.

The researchers also noted that the correlation between higher temperatures and vision impairment was more prominent in individuals aged 65 to 79. For those aged 80 and above, the condition was not as noticeable.

This phenomenon was also more prevalent among males than females. Finally, researchers found the condition more pronounced in White Americans compared to Black Americans.

Why do warmer temperatures cause vision impairment?

The scientists acknowledge that the underlying cause for the link between temperature and vision impairment is not yet understood.

The study proposed several potential reasons. These include increased exposure to ultraviolet light, heightened air pollution, and a rise in infections.

They also considered the degradation of folic acid due to higher temperatures. However, this study’s design does not offer a clear understanding of how temperature impacts vision.

The research utilized data from six consecutive waves of the American Community Survey (2012-2017). They surveyed a nationally representative sample of American respondents aged 65 and older annually.

The final sample analyzed consisted of 1.7 million older adults living in the US. They all resided in their birth states.

The study asked about vision impairment in terms of blindness or serious difficulties in seeing, even with glasses. For average temperature data, the researchers combined data from the National Oceanic and Atmospheric Administration (NOAA) with that from the American Community Survey.

“We were quite taken aback by the strong correlation between temperature and vision impairment,” confesses Esme Fuller-Thomson.

“This new discovery raises more questions than it answers, including the nature of the connection between average county temperature and vision impairment. In future, we plan to explore if county temperature also correlates with other disabilities in older adults, such as hearing problems and limitations in daily activities.”

More about the impact of climate change on human health

Climate change is affecting human health in many profound ways. Rising temperatures are causing more heat-related illnesses. Heat waves can lead to dehydration, heat exhaustion, and even deadly heat strokes.

Increased air pollution from wildfires and dust storms, intensified by climate change, can harm the lungs. It can lead to respiratory issues like asthma and other chronic pulmonary diseases.

Environmental toxins

Warmer climates promote the growth of harmful algae in the water we use for swimming or drinking. These algae can produce toxins that cause sickness when people drink the water or when it contacts skin.

Widespread diseases

Climate change also increases the range of disease-carrying insects like mosquitoes. As a result, diseases like Zika, West Nile virus, dengue, and malaria are reaching people in areas where these diseases were previously unknown.


Extreme weather events, such as floods and hurricanes, are becoming more common due to climate change. These events can cause injuries and deaths. They can also disrupt essential services, like electricity and healthcare, leading to indirect health effects.

Food insecurity

Changes in climate can lead to food insecurity too. Droughts, floods, warming temperatures, and changing rainfall patterns make it harder to grow crops in many regions. This scarcity can lead to malnutrition and starvation.

Sea level rise

Rising sea levels, another consequence of climate change, can force people to leave their homes. This displacement can lead to mental health problems, like anxiety and depression.

Longer allergy seasons

Climate change is also causing longer pollen seasons, leading to prolonged allergic reactions. These can cause discomfort and serious health complications in some individuals.

In conclusion, climate change is not just an environmental issue. It is a significant public health threat. Addressing climate change could help improve the health and well-being of people all over the world.

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