Air pollution may be harmful to children's eyesight, while cleaner air may help protect and even improve their vision, a new study suggests.
In particular, exposure to air pollutants - specifically nitrogen dioxide and fine particulate matter (PM2.5) - was associated with how well children could see without glasses, researchers reported in PNAS Nexus.
Genetics and lifestyle factors, such as screen time on electronic devices, are known to play a major role in whether children have myopia, or short-sightedness, in which distant objects appear blurry.
Using advanced machine learning techniques to study air pollution exposure in nearly 30,000 school-aged children, the research team discovered that environmental factors also matter.
After accounting for other myopia risk factors, they found that lower levels of nitrogen dioxide and fine particles in the air were independently associated with better vision.
They also found that primary school students and children with mild-to-moderate myopia benefit more from cleaner air than highly myopic or senior school students, suggesting that early action before vision problems become severe can make a difference.
The study can't prove that air pollution caused myopia.
Still, it is among the first to isolate air pollution as a meaningful and modifiable risk factor for childhood myopia, study leader Professor Zongbo Shi from the University of Birmingham in the UK said in a statement.
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 may have the potential to improve eye health, the researchers said.
"Clean air isn't just about respiratory health, it's about visual health too," Shi said.
