People who undergo incisional surgery for glaucoma and live in areas with elevated levels of oxidative air pollution may be more likely to have the procedure fail than patients who live in areas with cleaner air, a study of California Medicare patients found.

“Our study provides population-based evidence that ambient oxidative air pollution, particularly ground-level ozone [O₃], may be associated with long-term risk of surgical failure after incisional glaucoma procedures,” said Ken Kitayama, MD, PhD, a resident at the UCLA Stein Eye Institute who presented the findings at American Glaucoma Society (AGS) 2026 Annual Meeting.

The study used a retrospective cohort of 5958 patients drawn from the entire population of 2016-2018 California fee-for-service Medicare beneficiaries who had a claim for trabeculectomy or glaucoma drainage device surgery. It also used 2015 data on average annual outdoor concentrations for ground-level O₃, nitrogen dioxide (NO₂), and fine particulate matter (PM_2.5), averaged by beneficiary zip code. Surgical failure was defined by claims for revision or reoperation.

More Pollution, More Risk

Each increase in O₃ exposure of 10 parts per billion was associated with a 27% increased risk for failure, Kitayama said. A similar increase in exposure to NO₂ resulted in an 11% increased risk for failure; each 10 microns per cubic meter increase in fine particulate matter a 25% increased failure risk.

However, when the researchers conducted a multi-pollutant model analysis, only the association with O₃ remained significant, with a 31% increased for surgical failure, Kitayama said.

The study is one of the few studies to evaluate the impact of airborne pollutants on glaucoma surgery outcomes, Kitayama said.“Most prior work on air pollution and eye health has focused on the ocular surface and glaucoma risk,” he told Medscape Medical News.

“Studies have linked exposure to pollutants such as fine particulate matter and nitrogen dioxide to dry eye symptoms, ocular surface inflammation, and, in some cases, increased risk of glaucoma,” Kitayama said. Toxicology studies have also shown the pollutants can cause oxidative stress and inflammation in exposed tissues, he added.

Because the study was observational and used claims data, it does not establish a causal link between air pollution and surgical failure, Kitayama said.

“That said, the associations we observed occurred at pollution levels commonly experienced in California,” he said. “Our findings suggest that environmental context may play a role in variability in surgical wound healing.”

Further research would include replicating the findings in other populations and mechanistic studies exploring how chronic oxidative exposure might influence subconjunctival fibrosis, Kitayama said.

‘Novel’ Study

“This is the first study to my knowledge to investigate this correlation,” said Cara Capitena Young, MD, a glaucoma specialist at the UCHealth Sue Anschutz-Rodgers Eye Center in Aurora, Colorado.

Drawing a correlation between failure of glaucoma surgery and specific environmental factors is “hugely important,” Young said. “This could change our practice, especially for providers working in urban areas of areas with higher particulate matter and ground-level ozone.”

Kitayama’s study and a 2024 study by Young’s University of Colorado colleague Malik Y. Kahook, MD, which found a correlation between particulate matter pollutants and increased visits to eye clinics, could give ophthalmologists reason to evaluate causes for patients’ ocular complaints, she said.

“Glaucoma providers or any surgeon who works in the subconjunctival space may more strongly consider maximizing the health of the ocular surface through various methods preoperatively and postoperatively in order to improve surgical success rates,” she said.

A limitation of the study is that it looks at a California-only population, Young said. “Additional studies could expand findings to other areas and could further investigate confounders of surgical failure like ethnicity and previous subconjunctival surgeries,” she said.

The findings could also give reason for glaucoma surgeons to consider all options depending on a patient’s risk factors for failure, said Manjool Shah, MD, a glaucoma specialist at the W.K. Kellogg Eye Center at the University of Michigan in Ann Arbor, Michigan.

“One of the considerations that we never really thought of was, where do you live? What’s the air quality like?” Shah said. “As we have more and more nuance to our interventional toolkit, it stands to reason that we should certainly think about factors like a patient’s environment.”

This study was funded by Research to Prevent Blindness and the Hintz Fund. Kitayama, Shah and Young reported having no relevant financial conflicts of interest.

Richard Mark Kirkner is a medical journalist based in Philadelphia.