Dry Eyes Can Cause Tearless Trauma

Crying is a natural response to many situations, but a common eye problem is preventing many of us from shedding tears.

"Dry eye is a condition that affects about 10 percent of the population between the ages 30 and 60," said Dr. Stephen Pflugfelder, a professor of ophthalmology at Baylor College of Medicine in Houston. "Over the age of 65, it runs even higher, about 15 percent."

With a grant from the National Eye Institute of the National Institutes of Health, Dr. Pflugfelder is currently involved in several research projects targeting tears.

"We're identifying the key elements in tear production that keep the surface of the eye healthy and examining what happens when eyes become dry," Dr. Pflugfelder said. "Perhaps the most exciting phase is cell therapy, where we take cells, grow them in the laboratory, and actually transplant them on the surface of the eye to stimulate tear production."

When tear glands shut down, the eye surface becomes inflamed. Symptoms range from mild irritation to near blindness. In some cases, the dryness is so severe that ulcers form or cloudiness appears on the cornea, resulting in distorted vision.

"Tears serve an important function because they nourish the surface of the eye," Dr. Pflugfelder said. "Without this fluid, the eye is left unprotected."

A number of factors cause the tear glands to slow or even halt production. For many, air conditioning can dry out the eyes. Medications such as antihistamines and some anti-depressants can do the same.

Hormonal changes brought on by menopause can cause dry eyes in older women. Others susceptible to dry eyes include people suffering from diseases such as rheumatoid arthritis, lupus or neurological disorders, and those who wear contact lenses.

"Wearing contacts can cause the eye to grow numb, and there's no sensation to stimulate tear production," Dr. Pflugfelder said.

Dr. Pflugfelder noted that some patients who undergo laser surgery to correct vision have reported dryness in their eyes.

"Dry eye is mentioned as a side effect of procedures such as LASIK, but it's usually a temporary one," Dr. Pflugfelder said.

Although most people with dry eyes can be treated with common eye drops, many don't respond. Anti-inflammatory agents such as cyclosporin and antibiotics like tetracycline have been used effectively. But Dr. Pflugfelder said even those drugs don't work on everyone.

"I liken the eyes to flowers in a garden," Dr. Pflugfelder said. "If you don't provide the water and fertilizer, the flowers aren't going to thrive and will eventually dry out. That's more or less what happens without tears."

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©2006 Texas Medical Center

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