OHSU Researcher Helps Uncover Cause of Dry Eyesating in OHSU Drug Testing Study

10/04/00    Portland, Ore.

For the 10 million Americans who suffer from dry eye syndrome, tears are often a relief instead of a sign of distress. The condition, which is caused by a decline in the quality or quantity of tears bathing the eye, can cause constant pain from eye irritation. In extreme cases, patients can suffer scarring on the cornea and loss of visual function. However, physicians have so far been unable to pinpoint the exact cause of this common problem. Now a researcher at Oregon Health Sciences University's Casey Eye Institute has uncovered some answers to the questions about this mysterious condition.

According to William Mathers, M.D., a professor of ophthalmology in OHSU's School of Medicine, dry eye syndrome is a problem that feeds upon itself. "The lack of tears in the eye leads to damage of the cornea," said Mathers. "This damage can then affect function of the lacrimal gland, which manufactures tears. The whole process acts like a feedback loop, resulting in both dry eyes and corneal damage."

According to Mather's research, several mechanisms are involved in this complex process, including interruption or damage to nerves in the lacrimal glands, which secrete tears; damage to nerves in the cornea; and aging and autoimmune disease. In addition, contact lens and corneal refractive surgery to correct farsightedness or nearsightedness may play a role.

Mathers and his fellow researchers at OHSU studied information obtained from 520 patients in the Department of Ophthalmology at University of Iowa Hospitals and Clinics while Mathers was on faculty at that institution. He used this information to assess the relationship between dry eye and damage to the cornea. Scientists measured tear flow, tear evaporation rates and tear volume among these patients.

"After studying hundreds of people with varying levels of dry eye syndrome, we were able to come up with a complex model explaining how the problem progresses and the many factors involved," said Mathers. "However, much more research is needed to explore the ramifications of this theory. Once we fully understand this process, we can design a treatment strategy for each individual patient."

This research was funded by the National Eye Institute, a component of the National Institutes of Health .The research is published in the July 2000 edition of the Contact Lens Association of Ophthalmology Journal.