Air pollution linked to higher risk of myopia in children, study finds

A large study published in PNAS Nexus links air pollution exposure to higher rates of myopia in children, with younger eyes more vulnerable. Researchers analyzed PM2.5 and NO2 levels alongside vision tests in nearly 30,000 students across China and found that pollution exposure is associated with both the development and severity of myopia. The study also found that reducing air pollution by about 20 percent could improve vision scores among children and may slow progression to more serious eye disease later in life.

Between March 2021 and December 2023, 29,971 children in elementary, middle, and high school were enrolled. About 70 percent were in elementary school, 52 percent were boys, and nearly two-thirds had at least one parent with myopia. About 85 percent of participants lived in urban areas. The team measured uncorrected visual acuity and diagnosed myopia in 53 percent of participants. They also tracked ambient PM2.5 concentrations—tiny particles produced by fossil fuel burning and wood burning—and NO2, a gas formed by vehicle and industrial emissions. China has PM2.5 levels six times the World Health Organization safe limit and is the world's largest emitter of greenhouse gases, responsible for about 27 percent of global emissions.

The analysis showed NO2 and PM2.5 were the strongest predictors of myopia in children. Environmental pollution appeared more closely linked with myopia than genetics for milder cases, while severe myopia remained largely driven by non-modifiable factors such as genetics and younger age. Access to green space outdoors was associated with clearer vision.

In the breakdown, about 81 percent of severe myopia cases were associated with non-modifiable risk factors; environmental influences accounted for about 4.3 percent of severe myopia. For milder myopia, environmental factors explained around 12 percent, and behavioral factors such as sleep and time spent outdoors accounted for about 13.6 percent. PM2.5 exposure was linked to roughly 44 percent more mild myopia cases compared with severe myopia. The researchers also used machine learning to simulate cleaner air scenarios and found that reducing NO2 and PM2.5 by 20 percent improved overall vision scores.

The team notes that roughly a quarter of mild myopia risk in schoolchildren could be attributable to modifiable environmental and behavioral factors, nearly double the share in high myopia. The researchers argue that protecting children's eyes from pollution during key development years could yield meaningful vision benefits, complementary to established steps such as appropriate screen use and outdoor time.

Co-lead author Yuquing Dai of the University of Birmingham said that while genetics and screen time are recognized contributors to childhood myopia, this study highlights air pollution as a meaningful, modifiable risk factor. He said improving air quality could be a valuable intervention to protect eyesight, particularly during the most vulnerable developmental years.

Professor Zongbo Shi, another co-author and a specialist in atmospheric biogeochemistry at the University of Birmingham, said clean air isn’t just about respiratory health; it matters for visual health too. The study’s authors caution that while they cannot change a child’s genes, policy measures to reduce pollution could make a real difference in preventing vision impairment.

The findings add to a growing global concern about myopia, which is rising in many parts of the world. If policymakers act early to improve air quality and expand access to green spaces, researchers say children’s eyesight could benefit in a measurable way without sacrificing economic growth.