Can living in an area with high air pollution prematurely age your eyes? An ongoing population study of older adults in France suggests that, in addition to lifestyle, family disease history, and underlying medical conditions, where a person lives can influence their eye health.*

Air pollution and eye disease

Air pollution is largely made up of gases and particles that are released by fossil fuels that haven’t burned completely. This pollution is a major threat to human health, with an estimated seven million annual deaths globally, according to the World Health Organization (WHO). In 2021, WHO significantly lowered its recommended safe levels for airborne fine particulate matter and nitrogen dioxide to five and 10 μg/m3 (micrograms per cubic meter), respectively.

In an article published in the journal Environmental Research, French and Swiss researchers explain that, while air pollution’s negative lung and cardiovascular effects are well-documented, mounting evidence shows that the central nervous system can also be impacted from chronic exposure. 

This can result in neurodegenerative diseases like glaucoma, in which the optic nerve (eye-brain connection) is irreparably damaged. Several studies have specifically pointed to a link between air pollution and glaucoma risk.

What the researchers did

Led by the French research institution Inserm and the University of Bordeaux, the researchers sought to further understand how air pollution might lead to glaucoma.

In a long-term population study involving 683 residents aged 75 and older in Bordeaux, the research team explored potential links between glaucoma and other age-related eye diseases for links to nutritional, environmental, genetic, and vascular factors.

• Progressive thinning of the retinal nerve fiber layer (RNFL), a principal trait of glaucoma, was measured.
• Eye exams to measure changes in RNFL thickness were conducted once every two years using optical coherence tomography.

What they found

Residents who lived in areas of higher air pollution were found to be at potentially increased risk of developing glaucoma.

Specifically, RNFL was found to thin more quickly in people who had been exposed to greater amounts of fine particulate matter air pollution during the 10 years prior to the study.

The average baseline RNFL was 90 μm (micrometers), with an average rate of RNFL thinning at -0.28 μm/year.

What it means

The researchers concluded that their study provided additional evidence of a “strong association” between chronic exposure to fine airborne particulate matter and retinal neurodegeneration, even at levels below the current European Union-recommended safe threshold of 25 μg/m3. 

This suggests, they say, “a possible increase in the risk of glaucoma for people living in areas polluted by fine particles,” even at established safe levels. The potential harm to the central nervous system from air pollution, they add, can increase not only neurodegenerative disease risk in adults but also neurodevelopmental disorder risk in children.

Lead investigator Laure Gayraud said the team’s results support the argument for following WHO’s recommendation of lowering current air pollutant thresholds in Europe, and reducing French people’s actual exposure. 

The results arrive against a backdrop of harsh criticism from activists against French government officials for easing air pollution restrictions in most low-emission zones.

*Thompson, H. (2023, July 23). Dirty air could speed up the ageing of eyes says new French study. The Connexion. https://www.connexionfrance.com/article/Practical/Health/Dirty-air-could-speed-up-the-ageing-of-eyes-says-new-French-study