Reducing air pollution may be associated with better visual outcomes in children, particularly those of primary school age, according to a  new study (Chen et al, 2025).

While genetics remains the strongest risk factor for myopia, environmental influences such as near work, reduced time outdoors, natural light exposure and air pollution have also been implicated, though evidence has been mixed.

A team based in the UK and China used machine learning to rank factors associated with poor uncorrected visual acuity in almost 30,000 schoolchildren aged seven to 13 years in Tianjin, China.

Parental myopia ranked highest, followed by residence in areas with low night-time light levels (used as a proxy for socioeconomic status). This indirect measure should be interpreted cautiously.

Exposure to nitrogen dioxide (NO₂) and fine particulate matter (PM2.5) from burning fossil fuels, factories and domestic heating ranked next. These pollutants have previously been linked to myopia through mechanisms including oxidative stress, inflammation and reduced natural light exposure (Yuan and Zou, 2022).

Primary school-aged children appeared particularly sensitive to pollution exposure, with younger children predicted to gain the greatest improvement in uncorrected visual acuity from cleaner air.

Reliance on questionnaires and background pollution exposures may undermine confidence in some of the study’s findings. Estimated benefits of cleaner air were very small and the average pollution exposure levels in the study were much higher than in most countries, making it unclear how applicable the results are beyond China.