Exposure to air pollutants may contribute to eye disease. Photo: Getty Images.

Air pollution is known to be a major contributor to global disease, including those affecting the eye. A recent meta-analysis identified three ocular age-related conditions that may be associated with close exposure to air pollution: cataracts, age-related macular degeneration (AMD) and glaucoma.

The researchers reviewed several databases for papers on any of the three age-related eye diseases and evidence of an association with different ambient air pollutants (CO, NO₂, SO₂, O₃, PM_2.5, PM₁₀). Eight studies on patients 40 and older were included in the results. Overall, the researchers noted that they provided consistent evidence of an association between exposure to various air pollutants and incidence of cataracts, AMD and glaucoma.

“Consistent evidence for an association was found between PM_2.5 and glaucoma, with four of four studies reporting a positive association,” the researchers reported in their paper. They wrote that the pooled odds ratio for each 10μg/m³ increase of PM_2.5 on glaucoma was 1.18.

On the other hand, they observed consistent evidence for a possible protective effect of higher levels of O₃ on the development of cataract, with three of the studies reporting an inverse association. “Two of two studies reported a null association between PM_2.5 and cataract, while one of one studies reported a positive association between PM₁₀ and cataract,” the researchers noted in their paper. “One of one study reported a positive relationship between CO and AMD.”

Longitudinal data is needed to confirm the connection between exposure to each of these specific pollutants and the incidence of age-related disease. Still, these findings contribute to existing evidence suggesting that an association may be present.

Grant A, Leung G, Freeman EE. Ambient air pollution and age-related eye disease: a systematic review and meta-analysis. Invest Ophthalmol Vis Sci. August 12, 2022. [Epub ahead of print].