Four people who suffered a painful eye infection linked to the use of non-sterile contact lens solutions have been successfully treated with a drug used to treat skin diseases, doctors report.

Clotrimazole, an antifungal agent, was found by University of Florida professors to be effective against acanthamoeba keratitis, a potentially blinding corneal infection closely linked to the use of non-sterile contact lens solutions.Dr. William Driebe, assistant professor of ophthalmology at Florida's College of Medicine, combined clotrimazole with two drugs that are more commonly used after conventional therapies failed to stop a particularly ravaging infection in one of his patients. He said it was the first time the drug was successfully used to treat the infection.

The infection causes what has been described in a recent issue of "Archives of Ophthalmology" as "the kind of pain that causes the patient to stay in a dark room with the shades drawn, not venturing out for anything but the bare necessities." Driebe reported his findings in that publication.

Some patients have reported addiction to narcotics and loss of jobs and families as consequences of the terrible pain associated with acanthamoeba infection.

"Eyes have been lost from this infection, and, although clotrimazole is helping us to treat it more effectively, we're still fighting an uphill battle. The best solution, obviously, is prevention."

Prevention, Driebe said, is possible in 99 percent of the cases where acanthamoeba keratitis might occur.

The greatest risk factor is the use of non-sterile saline solutions to rinse and store contact lenses. Each of Driebe's acanthamoeba patients prepared their own contact lens solutions, using distilled water and salt tablets.

This method, while once advocated by some practitioners as a reasonable and inexpensive alternative to commercially available sterile saline, places users at a much greater risk for bacterial, fungal and amoebic infections.

Working with the Centers for Disease Control in Atlanta, Driebe said researchers there "had found that clotrimazole was the most active agent against this particular organism."

But clotrimazole was not available in an ophthalmic preparation. So Driebe sought approval to formulate a 1 percent solution, using a powdered form obtained from the drug manufacturer.

"Once we had permission, we made a suspension of the drug with artificial tears," he said. "At that point, my patient had undergone two corneal transplants in our efforts to halt the infection, which was not responding to standard medications.

"When we added the clotrimazole to his treatment, the response was dramatic," said Driebe, a corneal specialist and director of the contact lens service at the University of Florida Clinic's Eye Center.

Driebe's first acanthamoeba patient, Dr. John Graham-Pole, has been free of the infection for more than a year, and has 20/20 vision with corrective lenses. Since Graham-Pole's initial treatment, three additional patients have undergone successful treatment at the Eye Center with drug combinations containing clotrimazole.

In each case, vision has been restored to normal or near normal, and the patients remain free of symptoms.

"The infection is terribly painful," said Graham-Pole, associate professor of pediatrics at the university's College of Medicine, who was first diagnosed with acanthamoeba keratitis in 1986.

"At one point I couldn't do anything at all, essentially. I couldn't work, couldn't open my eyes in the light. I knew I might lose the eye," he said. "But, at times, the pain was so severe that I thought I would rather have the eye out than endure it any longer."

Driebe said although most infections of the cornea are fairly treatable, acanthamoeba has the ability to shift from a live form to a cyst stage, resistant to medication.

"As a result, you have to treat these infections for more than a year in order to destroy the organism. And on occasion, despite the best of medical therapy, the organism can progress, causing perforation of the cornea and necessitating corneal transplantation."