New research suggests residents of the most polluted cities in the U.S. have a higher chance of suffering from dry eye syndrome than country dwellers. 

Dry eye syndrome is a deficiency in tear production, it can cause extreme discomfort and interfere with sufferers' everyday lives, an American Academy of Opthalmology news release reported. 

The condition affects about four million people over the age of 50 in the U.S. This new study, suggests people living in places like Chicago and New York City are three to four times more likely to suffer from dry eye syndrome than those living in areas with less air pollution.

The research team looked at data from the National Veterans Administrative (VA) database, the National Climatic Data Center and National Aeronautics and Space Administration (NASA) to reach their conclusion. They found those living in metropolitan or other highly-polluted areas had a higher rate of dry eye syndrome with an incidence rate ratio of 1.4. 

Between 17 and 21 percent of people living in New York City, Chicago, Los Angeles and Miami suffered from dry eye syndrome. 

The team also found the risk of dry eye syndrome was 13 percent greater in high-altitude regions.

"Undoubtedly, many people living in arid and polluted cities would readily attest to the irritating effect air pollution has on dry eye," Anat Galor, M.D., MPSH, of Miami Veterans Affairs Medical Center, Assistant Professor of Clinical Ophthalmology Bascom Palmer Eye Institute, and lead researcher, said. "Our research suggests that simple actions, such as maintaining the appropriate humidity indoors and using a high-quality air filter, should be considered as part of the overall management of patients suffering from dry eye syndrome."

Those suffering from dry eye syndrome can experience stinging, burning, excessive tearing, and discomfort wearing contact lenses. The eye may tear excessively in an attempt to combat the irritation and loss of moisture.