Air Pollution Linked to Higher Risk of Glaucoma and Cataract

People who live in areas with higher levels of air pollution are more likely to develop glaucoma and cataract, a new study suggests.

“We’ve known for years that air pollution damages the lungs and heart, but its effects on the eyes have been much less studied, and the existing evidence was scattered and inconclusive,” Ahmed Alnabihi MD said.

“Every day, we see patients losing vision to conditions like glaucoma and cataract. These diseases are labelled as ‘age related’ as though ageing is the only culprit, but that always felt incomplete to me. If something environmental is accelerating these conditions, that changes our thinking and suggests we could take action to reduce the risks.”

Dr Alnabihi presented a systematic review and meta-analysis of 41 separate observational studies, drawing on data from millions of people across East Asia and the UK, including some of the world’s largest eye health databases.

Researchers analysed the levels of several types of air pollution: particulate matter, nitrogen dioxide, sulphur dioxide, ozone, and carbon monoxide. They compared these with how many people were diagnosed with glaucoma, cataract, or age-related macular degeneration.

Their analysis showed that the higher the levels of fine particulate matter, the greater the risks of glaucoma. People living in the most polluted areas had up to 70% higher odds of glaucoma than those in the least polluted areas. People living in more polluted areas also faced a consistently higher risk of developing cataracts, with risk increasing as pollution levels rose.

“The clearest finding was for fine particulate matter—the tiny particles in smoke, vehicle exhaust, and industrial pollution that are small enough to get deep into the body,” Dr Alnabihi said, adding that for every meaningful step up in pollution exposure, the risk of glaucoma rose by around 8% and cataract by around 4%. The evidence for age-related macular degeneration was less consistent, although some of the research supported a link. Other pollutants, including nitrogen dioxide and ozone, showed weaker or more mixed associations.

“Fine particles are thought to cause inflammation and oxidative stress in the body. Over years of exposure, these effects may damage the optic nerve, which is relevant to glaucoma, or the lens, which is relevant to cataract,” Dr Alnabihi said. “Unlike most other organs, the eye is directly open to the environment. The ocular surface—the tear film, conjunctiva, and cornea—has no barrier between it and outdoor air. That makes the biological plausibility here stronger than for some other organs.”

These findings add weight to the case for tighter air quality standards and pollution-reducing measures such as green spaces and traffic reduction in cities.

“Our paper adds a new organ system to that conversation,” Dr Alnabihi said. “Policymakers who need to justify investment in emission controls now have one more evidence-based reason to do so, and it’s one that affects our vision—a sense people are particularly afraid of losing.”

Ahmed Alnabihi MD practices at the King Khaled Eye Specialist Hospital and Research Center, Riyadh, Saudi Arabia.