Air Pollution: Eye Problems And Hazards Explained

Air pollution can have a detrimental impact on eye health, causing both short- and long-term issues. The eyes are constantly exposed to the open air, leaving them vulnerable to pollutants such as smoke, ozone, and nitrogen dioxide. While there is no way to avoid exposure to the open air, understanding the risks and taking protective measures can help maintain eye health.

Air pollution can cause minor to severe damage to the eyes, with higher levels of air pollution associated with increased instances of conjunctivitis. Common air pollutants, including nitrogen dioxide, carbon monoxide, and particulate matter, can trigger eye irritation and inflammation, leading to conditions such as dry eye and allergic conjunctivitis.

Long-term exposure to air pollution may also increase the risk of developing age-related macular degeneration (AMD) and glaucoma, as pollutants can enter the bloodstream and damage the small blood vessels within the eye. Additionally, the depletion of the ozone layer due to air pollution increases UV exposure, contributing to the development of cataracts and other eye conditions.

Protective measures, such as wearing glasses or sunglasses, avoiding contact lenses during poor air quality, and staying indoors when possible, can help reduce the harmful effects of air pollution on the eyes.

Air pollution can cause conjunctivitis

Common air contaminants that can cause conjunctivitis include sulfur dioxide, nitrogen dioxide, particulate matter, and high ozone levels. A study in South Korea found that carbon monoxide exposure was the most highly associated with the prevalence of conjunctivitis. Other studies have also found that increases in PM2.5, PM10, NO2, SO2, and O3 were significantly associated with the increase of conjunctivitis outpatient visits.

Dry air from air pollution can cause chronic dry eye

Living in arid areas or frequent exposure to dry air can worsen this condition and make the eyes more susceptible to other air irritants. Dry air primarily affects the tear film, causing eye problems like blepharitis or eyelid inflammation and meibomian gland dysfunction, which is the inflammation of the glands that produce tears.

Air pollution includes a complex mixture of particulate matter and harmful gases. The two well-established particulate matter sizes, PM2.5 and PM10, have different target organs. PM2.5 can reach the circulatory system, while PM10 does not, and its effects are restricted to the pulmonary system.

Several studies have found a link between a dry eye diagnosis and air pollution. However, one limitation in using diagnostic codes to diagnose dry eye is the inability to examine which facet of dry eye is related to air pollution.

There is also a strong link between indoor PM exposure and painful dry eye symptoms. Several studies across different countries and building situations have reported a link between office and home PM exposure and dryness and irritation.

The mechanisms by which air pollution may affect the ocular surface can be inferred from data generated outside the eye, where exposure to reactive gases can lead to cell death, oxidative stress, and inflammation.

Car exhaust gases can increase the risk of AMD

A study from Taiwan found a close relationship between two major air pollutants, carbon monoxide and nitrogen dioxide (the primary car exhaust fumes), and AMD. Another study found that individuals living in populated areas are 8% more likely to develop AMD.

The increase in carbon monoxide emissions is often observed during the cold winter months when engines take longer to warm up and run cleanly. Older engines are usually bigger offenders when it comes to carbon monoxide emissions.

Exposure to UV rays from air pollution can cause cataracts

Cataracts are a clouding of the eye lens that typically occurs with aging. The proteins inside the lens cells become damaged and clump together, scattering light rather than transmitting it. This results in symptoms such as foreign body sensation, itching, light sensitivity, burning, and redness due to rubbing the eye.

The sun's ultraviolet (UV) rays are known to cause skin damage, but they can also increase the risk of cataracts and other eye conditions. Prolonged exposure to UV rays from the sun can trigger oxidative stress in the lens, which is a major contributor to normal aging and age-related diseases.

The lens cells are mostly made up of water and proteins, and they lack the organelles typically found in other cells. This unique composition renders the lens transparent and capable of transmitting light to the retina. However, when the lens is exposed to UV rays, the proteins inside the lens cells undergo a process called glycation, which is typically seen in cataract formation and oxidative stress.

You are at a higher risk of developing cataracts if you:

• Live in areas with high levels of air pollution, particularly air pollutants such as carbon monoxide and nitrogen dioxide, which are primary car exhaust fumes.
• Live in highly populated areas, as individuals in these areas are more likely to develop cataracts.
• Are frequently exposed to UV rays, either directly from the sun or reflected from surfaces such as snow, ice, water, or sand.
• Have a familial history of cataracts or other eye diseases.
• Have existing eye conditions such as dry eye syndrome or conjunctivitis, which can make the eyes more susceptible to the damaging effects of UV rays.

• Routinely check weather forecasts and air quality reports before going outdoors. If the air quality is poor, consider rescheduling outdoor activities or using protective eye equipment.
• Wear sunglasses or protective eyewear that blocks or absorbs UV rays when spending time outdoors, even on cloudy days. Wrap-around styles or those with side panels can help block harmful rays from entering from the sides.
• Use a wide-brimmed hat or visor to provide additional protection for your eyes.
• If you wear contact lenses, consider switching to UV-absorbing contact lenses or wearing eyeglasses instead to reduce the risk of trapping particles in the eye.
• See an optometrist or eye care specialist regularly for eye exams to monitor eye health and catch any issues early on.
• Stay indoors and limit exposure to UV rays when the air quality is poor, especially if you have sensitive eyes or existing eye conditions.

By taking these precautions and being mindful of your exposure to UV rays and air pollution, you can help protect your eyes from the harmful effects of air pollution and reduce your risk of developing cataracts.

Air pollution can restrict blood flow to the eyes

High levels of air pollutants can block or restrict normal blood flow to the eyes, leading to eye stroke, retinal vein occlusion, and glaucoma.

A study has shown that a high concentration of airborne toxins can interrupt the blood flow in the eyes' blood vessels.

The eyes are very exposed and sensitive to pollutants in the air. The cornea is the most sensitive structure in the human body due to numerous innervations in the ocular surface. The eyes are therefore susceptible to the adverse effects of air pollution.

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