By Linda Conlin, Pro to Pro Managing Editor

This Photo by Unknown Author is licensed under CC BY-NC-ND

When it comes to air pollution and health, we most often think of its effects on our respiratory system, but consider that the eye is an organ with a surface constantly exposed to the environment. According to The Adverse Effects of Air Pollution, “Exposure to polluted outdoor air has been proven to be harmful to human eyes. On the other hand, indoor air pollution from environmental tobacco smoking, heating, cooking, or poor indoor ventilation is also related to several eye diseases...”  (Lin CC, Chiu CC, Lee PY, et al. The Adverse Effects of Air Pollution on the Eye: A Review. Int J Environ Res Public Health. 2022;19(3):1186. Published 2022 Jan 21. doi:10.3390/ijerph19031186) 

There are many different types of air pollutants, such as gases, particulates, and biological molecules. Among those found outdoors are sulfur dioxide, nitrogen dioxide, carbon dioxide, nitrogen monoxide, carbon monoxide, nitrogen oxides, and particulate matter. Interactions between those molecules also can cause eye irritation. These oxidants can dissolve in the tear film and acidify it, irritating the mucous membrane of the eye. Air pollution occurs indoors, too. In buildings with poor ventilation, tobacco smoking, household decorating and cooking, heating methods, and formaldehyde contribute to indoor air pollution, in addition to other health problems. 

Because of constant exposure to indoor and outdoor environments, the cornea is vulnerable to the effects of air pollution and are likely to be the first of our organs affected. Tear film is a defense against pollutants but can be overwhelmed by chronic inflammation, oxidative stress, and pollution toxicity.  Studies have shown that the most common ophthalmologic disorder related to air pollution was conjunctivitis. Outdoor pollutants have been linked to ocular surface disease, dry eye disease, glaucoma, and retinopathy. And indoor pollutants have been linked to those conditions as well as cataract and uveitis. What’s more, a study published in the Journal of Investigative medicine linked traffic-related air pollutants with an increased risk for age-related macular degeneration.

As we see increasing warmer and dryer weather patterns that contribute to events such as wildfires, the effects of the quality of the environment on the eye must become better known. To date, only a limited number of studies have investigated the relationship between air pollution and ocular diseases. For that reason, the long-term impacts of air pollutants on the eye are currently unknown. Further research on the association between air pollutants and ophthalmological disorders is needed to improve the understanding of exposure patterns and ocular effects. 

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