Air pollution exposure could increase risk of irreversible sight loss, study suggests

Exposure to air pollution could increase the risk of developing a form of irreversible sight loss in older age, researchers have claimed following a large-scale observational study.

The long-term research, published in the British Journal of Ophthalmology, found that air pollutants were linked to a heightened risk of age-related macular degeneration (AMD) – a progressive form of sight loss.

AMD is the leading cause of irreversible blindness in the over-50s in wealthy countries such as the UK, with known risk factors including older age, smoking and genetic predisposition.

The research drew on data from 115,954 participants of the community-based UK Biobank study which involves more than 500,000 people.

More than 52,000 people also had their eyes examined with retinal imaging to assess structural changes in the thickness and numbers of receptors in the retina which are indicative of AMD.

The study found that just over 1 per cent of the overall participants (1,286 people), who were aged between 40 and 69 at the start of the study and had no eye problems, were diagnosed with AMD.

Once other factors such as lifestyle and underlying health conditions were taken into account, analysis found that participants exposed to higher levels of concentrations of the pollutant PM2.5 were 8 per cent more likely to report that they had been diagnosed with AMD.

PM2.5 and other pollutants were also associated with changes in the structure of people’s retinas.

“Overall, our findings suggest that ambient air pollution, especially fine particulate matter or those of combustion-related particles, may affect AMD risk,” the researchers said.

“Our findings add to the growing evidence of the damaging effects of ambient air pollution, even in the setting of relative low exposure.”

However, they noted that their research was an observational study and could not prove that pollution caused sight loss, although it echoed findings elsewhere in the world.

“Here we have identified yet another health risk posed by air pollution, strengthening the evidence that improving the air we breathe should be a key public health priority,” lead author of the study Professor Paul Foster, from University College London’s Institute of Ophthalmology, said.

“Our findings suggest that living in an area with polluted air, particularly fine particulate matter or combustion-related particles that come from road traffic, could contribute to eye disease.”

Prof Foster added: “Even relatively low exposure to air pollution appears to impact the risk of AMD, suggesting that air pollution is an important modifiable risk factor affecting risk of eye disease for a very large number of people.”

Chris Inglehearn, professor of molecular ophthalmology at the University of Leeds, said the study and another from Taiwan both showed a link between air pollution and age-related macular degeneration.

He added that the links did not prove pollution was causing AMD but the fact that the two independent studies reached similar conclusions gave “greater confidence” that the link was accurate.

“These studies provide further evidence that links air pollution with detrimental impacts on human health,” Prof Inglehearn said.

Additional reporting by PA