The Impact of the Environment on Chronic Dry Eye

Chronic dry eye (CDE) is a disease of the surface of the eye that can happen when your eye does not make enough tears or there is an issue with the tears that are made. Symptoms can include:^1,2

• Pain and discomfort
• Burning
• Dryness
• Blurry vision

CDE can be caused by a variety of reasons. Environment, weather, and pollution can greatly affect chronic dry eye.^1,2

Environment

Several environmental factors have been linked to CDE. This includes things like:³

• High altitude
• Seasons
• Forced air
• Certain weather
• Air pollution

Environment can also include wind, heat, and humidity.³

One study showed dry eye was more common in winter and spring, and less common in the summer. This suggests the seasons can play a role in CDE symptoms. High altitudes also lead to changes in the eye, including an increase in tear evaporation. When tears evaporate at a quicker than normal rate, dry eye symptoms can occur.⁴

Weather

Changes in weather and certain types of weather can affect chronic dry eye. This includes:⁵

• Humidity
• Wind
• Sunlight
• Extreme temperatures

In one European study, only 8 percent of people reported that weather did not impact their CDE symptoms. Most research shows that extreme temperature and humidity are not good for the eye. Minimal wind and sunlight, along with moderate humidity and moderate temperatures, make the best conditions for the eye.⁵

Dry climate and humidity

Dry climate can raise dry eye risk and worsen symptoms. Dry eye symptoms are linked to humidity levels. For example, when humidity levels rise, dry eye symptoms lessen.⁵

Indoor and outdoor environments with low humidity can cause CDE symptoms. Low humidity and dry air impact the tear film of the eye by increasing evaporation and reducing tear-film breakup time. This leads to dry eye symptoms. Humidity levels of 45 percent or more are best for eyes.⁶

Sunlight, wind, and heat

Some weather conditions like sunlight, wind, and high heat can lead to symptoms of dry eyes. One study found that people living with CDE saw the chance of symptoms double when they were exposed to excessive wind and sunlight.^4,8

Pollution

Both indoor and outdoor air pollution can have negative effects on CDE signs and symptoms. Doctors think overall management of dry eyes should include reducing exposure to pollutants. This can include things like:⁴

• Changing a walking or driving route
• Using an air purifier
• Getting indoor plants
• Clearing areas with mold and dust

Outdoor pollution

Natural and human-made substances like pollen, mold spores, gas fumes, and other chemicals are considered outdoor pollutants.⁹

One study showed people living in big cities with high levels of air pollution have an increased risk of dry eye syndrome. Within that study, people living in and near Chicago and New York City were 3 to 4 times more likely to be diagnosed with dry eye syndrome when compared to people in more rural areas with less air pollution.¹⁰

Indoor pollution

The link between indoor pollutant exposure and painful CDE symptoms is strong. Mold, dust, cigarette smoke, and cleaners can irritate and harm the surface of the eye.⁵

Things to think about

Various air pollutants and environmental conditions can harm the surface of the eye and affect the ability of the eye to lubricate and protect itself. Over time, the decrease in lubrication leads to chronic inflammation and irritation of the eye. This can lead to pain and vision problems, which can be common in those with CDE.^2,4