Dry-eye syndrome isn’t just about a lack of tears – just ask the 20 million Americans who suffer from it.

FORT WORTH, Texas – Many factors such as allergies, hormones and sunlight conspire to aggravate dry eyes.

You may also suffer from dry eyes if you work at a computer, exercise outside on a windy day, read, travel in a car with the air conditioner on or watch an outdoor football or baseball game, especially at night.

The National Women’s Health Resource Center, an independent nonprofit health information source, has made dry-eye a priority. That’s because dry eye affects many more women than men, said Elizabeth Battaglino Cahill, executive director of the center.

“Dry-eye syndrome, age-related macular degeneration, glaucoma and cataracts are all more prevalent in women,” Cahill said. “Dry eye is especially prevalent in post-menopausal women. A lot of it starts with hormonal changes.”

And dry-eye syndrome is not always characterized by a lack of tears. Sometimes, it’s the quality of tears that fail to properly lubricate the eye, said Dr. Cary Burton, a Fort Worth ophthalmologist with special interest in dry eyes. He calls the disorder “dysfunctional tear syndrome” because it sometimes causes an overproduction of inefficient tears.

If your tears are watery and do not adequately lubricate your eyes, the brain can send out an SOS to increase production, but the extra tears still do not keep the surface of the eyes properly lubricated, Burton explained.

Dysfunctional tear syndrome affects an estimated 20.7 million people in the United States.