Long-term exposure to air pollution could increase glaucoma risk, claims UK study

The research found that people living in areas with high particulate matter have a 6 per cent higher chance of developing glaucoma.

Pollution in Delhi | Photo: Praveen Jain | ThePrint

New Delhi: People living in areas with higher levels of air pollution are more likely to suffer from glaucoma, a debilitating eye condition that can cause blindness, claims a new study led by University College London.

Glaucoma is the leading cause of irreversible blindness and affects over 60 million people worldwide. It most commonly occurs  due to high pressure fluid build-up in the eye, which causes damage to the optic nerve that connects the eye to the brain. Glaucoma is a neurodegenerative disease and leads to progressive degeneration of the central nervous system.

According to the researchers, living in a polluted area with high levels of particulate matter increases the risk of developing glaucoma by 6 per cent.

“We have found yet another reason why air pollution should be addressed as a public health priority, and that avoiding sources of air pollution could be worthwhile for eye health alongside other health concerns,” said Paul Foster of UCL, lead author of the research published in the journal Investigative Ophthalmology & Visual Science Monday.

“While we cannot confirm yet that the association is causal, we hope to continue our research to determine whether air pollution does indeed cause glaucoma, and to find out if there are any avoidance strategies that could help people reduce their exposure to air pollution to mitigate the health risks,” said Foster.

“Most risk factors for glaucoma are out of our control, such as older age or genetics. It’s promising that we may have now identified a second risk factor for glaucoma, after eye pressure, that can be modified by lifestyle, treatment or policy changes,” he added.

PM2.5 increases risk of glaucoma

The findings were based on 1,11,370 participants across Britain who underwent eye tests from 2006 to 2010. The participants were asked whether they had glaucoma, and they underwent ocular testing to measure intraocular pressure (fluid pressure inside eyes), and spectral-domain optical coherence tomography imaging (a laser scan of the retina) to measure thickness of their eye’s macula (central area of the retina). A thinner retina is one of the changes typical of glaucoma progression.

The data was analysed with air pollution levels of their residential areas. The researchers focused on fine particulate matter such as PM2.5, which is equal to or less than 2.5 micrometres in diameter.

“Air pollution may be contributing to glaucoma due to the constriction of blood vessels, which ties into air pollution’s links to an increased risk of heart problems. Another possibility is that particulates may have a direct toxic effect damaging the nervous system and contributing to inflammation,” said Sharon Chua from UCL.

Air pollution has already been implicated in elevated risk of pulmonary and cardiovascular disease as well as brain conditions such as Alzheimer’s disease, Parkinson’s disease and stroke. Long-term particulate matter exposure has been termed as a global health hazard by several studies.

“Given that this was in the UK, which has relatively low particulate matter pollution on the global scale, glaucoma may be even more strongly impacted by air pollution elsewhere in the world. And as we did not include indoor air pollution and workplace exposure in our analysis, the real effect may be even greater,” said Foster.