Eyedrops can replace patches for treatment of `lazy eye'.

Byline: THE HEALTH FILES by Tim Christie The Register-Guard

WHEN I WAS A BOY, I wore an eye patch for a while. Not because I was into pirates, but because I had one weak eye and one strong eye, an ailment known as amblyopia. The patch went over the strong eye, to force the weaker eye to work and strengthen its focusing muscles.

Amblyopia - derived from the Greek word for "dullness of vision" - afflicts 2 percent to 3 percent of American children. It usually develops in infancy and early childhood, when the brain learns to favor one eye over the other, and it's the most common cause of visual loss in children and young adults.

For decades, the recommended therapy for amblyopia, sometimes called "lazy eye," has been the eye patch. Instead of the black, pirate-style patch with elastic strap that I wore, kids today often wear oval, flesh-colored patches which they can color and decorate with stickers. Or sometimes their eyeglasses are fitted with plastic or foam patches.

But there's a problem with patches: Most kids don't like to wear them and parents don't like making their kids wear them.

"Patching is very hard work for the family," said Dr. David Wheeler, an assistant professor of ophthalmology at Oregon Health & Science University's School of Medicine in Portland. "It often isn't carried out as it's prescribed."

That's why a study published last week in the Archives of Ophthalmology may change the way eye doctors treat amblyopia.

Researchers found that eye drops that blur vision in the child's strong eye were just as effective as an eye patch in correcting amblyopia. And they found parents generally preferred eye drops to the patch. The study, funded by the National Institutes of Health, was conducted at 54 sites around the United States, including at OHSU's Casey Eye Institute.

A medicine called atropine is used to dilate the pupil and blur vision by temporarily weakening the focusing muscle inside the eye.

"It's much easier to administer and much less disturbing to the child," said Wheeler, who was the study's principal investigator in Oregon.

While many patients now are likely to demand eye drops, the patch will probably remain the preferred therapy for children with severe amblyopia, Wheeler said.

Eye doctors have treated amblyopia by blurring a patient's vision for nearly a century, but mostly as a secondary treatment: A 1997 survey found that just 3 percent of eye doctors prescribed atropine as primary treatment. The study was the first systematic comparison of the two treatments.

Between April 1999 and April 2001, researchers looked at 419 children ages 6 years and younger diagnosed with moderate amblyopia. Half were treated with atropine eye drops and half wore patches. Researchers found visual acuity in the weak eye improved for most children in each group: 79 percent in the patching group and 74 percent in the eye drops group, a difference deemed clinically insignificant.

Most parents reported their children tolerated treatment well, but parents of children in the eye drop group generally were more satisfied with treatment than parents of children in the eye patch group.

The eye drops also have the advantage of being cheaper. The atropine treatment is estimated to cost $10 over six months, where an eye patch would cost nearly $100. About one in four atropine-treated patients may need to wear a special lens in their eyeglasses to compensate for the effect of the atropine, at a cost of about $50.

But perhaps the drops' key advantage is that once administered in the morning, there's nothing more to do. Children who wear a patch must be monitored because they frequently remove the patch, researchers said.

"You're covering up their good eye and they don't like that," said Dr. William Cox, a Eugene ophthalmologist. "It feels mean to them."

Researchers found the compliance rate to be good or excellent in 83 percent of patients who wore patches, and in 96 percent of the eye-drop group.

Still, for some eye doctors and their patients, the patch is likely to remain the preferred choice.

Carol Marusich, a Eugene optometric physician, said she prescribes atropine drops as a fallback if a child absolutely refuses the patch. But in her practice, the patch and variations on the patch will remain the preferred therapy for a simple reason.

"There are no side effects from the patch," she said. "Atropine is a pretty strong pharmaceutical treatment. ... It has side effects."

Some children suffer such chemical reactions, hallucinations or dry mouth, she said. Also, there are numerous techniques for making the patch a positive experience for children.

"You make it an exciting, cooperative activity," she said.

Molly Warner, a 6-year-old Corvallis girl, was diagnosed with amblyopia last year at a pre-kindergarten health screening. The eye doctor told her mother that Molly would be a good candidate for a study under way at Casey Eye Institute.

Molly was enrolled in the study and randomly assigned to the eye patch group. In Molly's case, that was a good thing, said her mother, Patti Warner.

"She didn't like the drops," Warner said, afraid they would sting her eyes. But Molly adapted to the patch quite easily, she said, perhaps in part because she liked the idea that she was a part of a study that could end up helping others.

"At the end she wanted to put them on by herself," Warner said.

After seven months on the patch, Molly's eyes improved so that with glasses, her vision was 20/20.

Tim Christie can be reached at 338-2572.