Report · Dubai Online
Air pollution may be affecting more than just heart and lungs. A new analysis of existing research suggests that exposure to polluted air, particularly fine particulate matter known as PM2.5, is associated with a higher risk of serious eye diseases, including glaucoma and cataracts. Researchers carried out a systematic review and meta-analysis to examine whether air pollution could be linked to common eye conditions, an area that has received far less attention than the well-established effects of pollution on cardiovascular and respiratory health.
The study was presented at the 44th Congress of the European Society of Cataract and Refractive Surgeons on Monday. To investigate the issue, they gathered and combined findings from 41 observational studies involving data from millions of people. The research included studies conducted in East Asia and the United Kingdom and drew information from some of the world's largest eye-health databases.
The authors stressed that the study does not prove air pollution directly causes glaucoma or cataracts. Because the analysis was based on observational studies, it can identify associations rather than establish cause and effect. The team examined exposure to several major air pollutants, including fine particulate matter (PM2.5), larger particulate matter (PM10), nitrogen dioxide, sulphur dioxide, ozone and carbon monoxide, comparing pollution exposure with rates of glaucoma , cataracts and age-related macular degeneration (AMD).
The strongest evidence emerged for PM2.5, which consists of microscopic particles commonly found in smoke, vehicle exhaust and industrial emissions. According to the analysis, higher levels of PM2.5 exposure were consistently linked to a greater likelihood of developing glaucoma. Dr.
Ahmed Alnabihi, author of the study from King Khaled Eye Specialist Hospital and Research Center in Riyadh, Saudi Arabia, told Newsweek: "The strength and consistency of the fine particulate matter (PM2.5) findings stood out, particularly for glaucoma, where the association was statistically significant with low variability across studies, which is unusual in this kind of pooled analysis." ... The researchers found that people living in the most polluted areas had up to 70 percent higher odds of glaucoma compared with those living in the least polluted locations. According to Alnabihi, for every meaningful increase in pollution exposure, the risk of glaucoma rose by around 8 percent.
A similar pattern was observed for cataracts . People exposed to higher levels of pollution were found to face a greater risk of developing the condition, with the likelihood increasing as pollution levels rose. Alnabihi said the risk of cataracts increased by approximately 4 percent for every meaningful increase in air pollution exposure.
The findings were less clear when it came to age-related macular degeneration. Some of the studies included in the review reported a connection between air pollution and AMD, but the overall evidence was less consistent than that seen for glaucoma and cataracts. Researchers also examined whether pollutants other than PM2.5 were linked to eye disease.
While substances such as nitrogen dioxide and ozone showed some associations, the evidence was generally weaker or more mixed than the results observed for fine particulate matter. Alnabihi noted that some findings involving other pollutants were less straightforward. "A few other pollutants, like ozone, showed mixed or even seemingly protective signals against cataract in some models, which is a genuine puzzle we flag as needing further research," he said.
The team proposed several biological explanations for the findings. According to the researchers, fine particles may trigger inflammation and oxidative stress throughout the body. Over time, these processes could damage the optic nerve, which plays a central role in glaucoma, or affect the lens of the eye, contributing to cataract formation.
They also pointed out that parts of the eye are directly exposed to the environment. Structures including the tear film, conjunctiva and cornea have no barrier separating them from outdoor air, which the researchers said makes a pollution-related effect biologically plausible. Alnabihi said glaucoma and cataracts are often viewed primarily as consequences of aging.
However, the findings suggest environmental factors may also contribute to the development of these conditions. He said: "We found that people living in more polluted areas face a meaningfully higher risk of glaucoma and cataract, two leading causes of vision loss worldwide,” adding that while both conditions are commonly regarded as age-related, the findings indicate environmental exposure may also play an important role. The researchers argue that the results strengthen the case for stricter air-quality standards, pollution-reduction measures, more green spaces and reduced traffic in urban areas.
Clean-air policies have typically been promoted because of their benefits for heart and lung health, but the team said eye health and vision should also be included in those discussions. According to Alnabihi, several key questions remain unanswered. He said additional studies are needed in under-researched but highly polluted regions, including South Asia, the Middle East and Africa.
Researchers also need to identify which cataract subtypes and disease mechanisms are most affected by pollution, as grouping all cataracts together may obscure important patterns. In addition, Alnabihi called for more genetic and other high-quality evidence to help determine whether the associations observed across eye diseases reflect a causal relationship. Contact Newsweek editors on this story: Kara Dolman and Emma Lee-Sang
Source: Newsweek
