Air pollution may be harming children's eyesight with cleaner air helping to protect and even improve their vision - especially in younger children, a new study reveals.
Researchers have discovered that exposure to lower levels of air pollutants - specifically nitrogen dioxide (NO₂) and fine particulate matter (PM2.5) - is associated with how well children can see without glasses.
Their findings suggest that reducing exposure to these pollutants could help slow the progression of myopia or short-sightedness - when distant objects appear blurry. The condition is becoming more common in children, especially in East Asia.
Publishing their findings in PNAS Nexus today (23 Sep), the experts note that, while genetics and lifestyle factors - such as screen time on electronic devices - play a major part in whether children have myopia, environmental factors such as air pollution also matter.
Using advanced machine learning techniques, the team examined how environmental, genetic, and lifestyle factors interact to influence children's vision development. The researchers discovered that children who lived in areas with cleaner air had better vision, after accounting for other factors.
They found that primary school students are especially sensitive to air pollution. These younger children showed the greatest improvements in uncorrected visual acuity when exposed to cleaner air.
In contrast, older students and those with high myopia were less affected by environmental changes, with their vision more strongly influenced by genetic factors - suggesting that early action—before vision problems become severe—can make a real difference.
Professor Zongbo Shi, from the University of Birmingham, who co-supervised this study, commented: "While genetics and screen time are long recognised as contributors to childhood myopia, this study is among the first to isolate air pollution as a meaningful and modifiable risk factor.
"Clean air isn't just about respiratory health—it's about visual health too. Our results show that improving air quality could be a valuable strategic intervention to protect children's eyesight, especially during their most vulnerable developmental years."
Polluted air can cause inflammation and stress in the eyes, reduce sunlight exposure - which is important for healthy eye development, and trigger chemical changes in the eye that lead to it changing shape, causing myopia.
This study suggests that installing air purifiers in classrooms, creating "clean-air zones" around schools to reduce traffic pollution, and closing streets to cars during school drop-off and pick-up times have the potential to improve eye health because children spend a lot of time at school.
Co-author Dr Yuqing Dai, from the University of Birmingham, commented: "Myopia is on the rise globally, and it can lead to serious eye problems later in life. While we can't change a child's genes, we can improve their environment. If we act early—before severe myopia sets in—we can make a real difference."
