Eye allergies are becoming dramatically more common, affecting up to 40% of people in North America, and climate change is a major culprit. Pollen seasons are starting earlier and lasting longer, plants are producing more potent pollen, and air pollution is making allergic reactions worse. Even people who never had allergies before are developing them well into adulthood.

Why Are Ocular Allergies Skyrocketing?

Ocular allergies, also called allergic conjunctivitis, have increased more than threefold over the past 20 years. This surge isn't due to genetics changing; rather, the environment around us has transformed dramatically. People who were genetically predisposed to mild allergies are now experiencing clinically significant symptoms that affect their daily lives.

"Our genetic makeup has remained essentially the same, so what has changed is important," said Leonard Bielory, MD, an allergist-immunologist and leading expert in ocular surface disorders.

Leonard Bielory, MD, Allergist-Immunologist

The primary driver is a fundamental shift in how plants behave. Due to global warming, spring arrives earlier while fall frosts are delayed, causing growing seasons to last longer and overlap. This means people are now exposed to multiple types of pollen simultaneously, rather than experiencing distinct seasonal allergies. Those who previously had allergies only during spring or fall now suffer year-round.

How Is Climate Change Making Pollen More Dangerous?

The problem goes beyond longer exposure. Higher concentrations of carbon dioxide in the atmosphere, combined with warmer temperatures, are causing plants to produce greater amounts of pollen. But that's not all. The pollen itself has become more allergenic and more fragile.

"Pollen is more potent than it was before. It has more fragile cell walls, and grains rupture more easily when they hit the eye, causing a sudden burst rather than the slower release of allergens that we saw in the past," explained Barbara C. Erny, MD, ophthalmologist at Stanford University.

Barbara C. Erny, MD, Ophthalmologist at Stanford University

Nitrogen dioxide in the air is also making pollen grains themselves more allergenic, leading to more severe allergic reactions. Additionally, plants are migrating to new regions. Ragweed, Bermuda grass, and maple trees, which are major causes of seasonal allergies, are now being found farther north and at higher altitudes than before, exposing new populations to allergens they've never encountered.

What Role Does Air Pollution Play?

Even if you live in an area with manageable pollen levels, air pollution can dramatically worsen your allergic reactions. The eyes are directly exposed to the environment with no filter other than tear film lubrication, making them vulnerable to irritants like particulate matter, carbon monoxide, nitrogen oxide, and ground-level ozone. These pollutants act as powerful amplifiers of allergic responses, turning mild allergies into moderate or severe ones.

Particulate matter in polluted air physically binds to pollen grains, making them more effective at penetrating the eye's protective barrier than pollen alone. Wildfires have made this problem even worse. After the Los Angeles fires in 2025, air pollution was 10 times more toxic, containing harmful chemicals like benzene, toluene, and formaldehyde that cause direct chemical injury to the cornea and conjunctival tissue, making it easier for allergens to penetrate and trigger mast cells to release histamine.

Microplastic particles in the air add another layer of harm. These particles bind to pollen grains and act as carriers of allergens to the eye. Because microplastics have jagged edges, they abrade the ocular surface while delivering pollen, making the allergic reaction worse.

How to Manage Rising Ocular Allergies

• Monitor Local Pollen Counts: Track pollen levels in your area using available air quality apps and pollen forecasts. Experts are developing home-based pollen detectors to create networks of pollen counts throughout the country, which will help you plan outdoor activities more effectively.
• Protect Your Eyes During High Pollen Days: Wear wraparound sunglasses to create a physical barrier between your eyes and airborne pollen and pollutants. This simple step can significantly reduce exposure to allergens.
• Reduce Screen Time: High screen usage is associated with increased prevalence of allergies in both adults and children due to tear film dysfunction and allergen exposure, so take regular breaks from digital devices.
• Seek Professional Diagnosis: If you're experiencing new eye symptoms, consult an allergist or ophthalmologist. Some people exposed to air pollution and pollen may develop ocular symptoms even if they test negative for traditional allergies.

What's Being Done to Address This Growing Problem?

The scale of ocular allergies varies significantly by region. In a study across the United States, researchers found ragweed sensitization ranging from 14% in the Northeast to as high as 54% in the West and 70% in the Midwest. Allergies to mold, grass, ryegrass, and cat dander have also increased, partly because more people now keep cats indoors.

Europe has a more coordinated approach to tracking these trends. The European Aeroallergen Network monitors pollen across more than 600 sites in 38 countries. The United States lacks a similar government-sponsored, centralized system, relying instead on individual initiatives. Experts are working to develop commercial pollen detection devices that can be used at home to create a nationwide network of pollen counts, which would help people make informed decisions about outdoor exposure.

An assessment of pollen trends in New Jersey showed that in just the past five years, the amount of pollen has increased by almost 10% annually. This upward trajectory underscores the urgency of both individual protective measures and broader environmental interventions to address the root causes of rising allergies.