May 12, 2003 -- Treatment for lazy eye in children is about to get much easier. A new study shows that wearing an eye patch for only two hours a day works just as well -- and just as fast -- as wearing the patch for six hours.
"Treatment now is going to be dramatically different," study leader Michael Repka, MD, tells WebMD. "It does stand to reason that wearing the patch longer is better. That is why these results are so surprising."
How convincing are the study results? Repka, professor of ophthalmology and pediatrics at the Johns Hopkins, says he's already changed the way he treats his patients. So has Scott Lambert, MD, director of pediatric ophthalmology at Atlanta's Emory Eye Clinic, one of the study's principal investigators.
Lazy eye -- amblyopia -- is the leading cause of vision loss in children. It happens when one eye doesn't see as well as the other. Usually it's because of a crossed or wandering eye (strabismus), or because one eye is much more nearsighted or farsighted than the other.
When this happens to young children, their brain stops processing signals from the weak eye. If allowed to go on long enough, the child permanently loses sight in the weak eye -- even if there's no physical damage to the eye. Fortunately, there's a treatment: Put a patch over the good eye, and force the child's brain to learn to see with the weak eye.
That's a problem for kids. First, wearing the patch means they can only see with their weak eye. This can be frustrating. Second, the eye patch leads to stigma. Other children tend to tease or stare at a kid who has to wear an eye patch.
But what if it took only a couple of hours of patch-wearing a day? Then kids could wait to wear the patch until they got home from school.
Repka and colleagues enrolled 189 children at 35 U.S. eye clinics. The kids' average age was 5 years, none was older than 7. They had what doctors call "moderate amblyopia." This means that their visual acuity was in the range of 20/40 to 20/80.
The kids were randomly assigned to wear an eye patch for two hours or for six hours. Even though textbooks say kids should wear the patch during every waking hour, Repka finds that most of his colleagues settle on about six hours a day.
Importantly, the kids didn't just wear a patch. They also had to spend two hours of patch time on eye-exercising tasks. These included coloring with crayons, doing connect-the-dot or find-the-hidden-object puzzles, or, for older children, doing homework.
After four months, both groups had the same amount of improvement: They could see two or three more lines on an eye chart than they could read before.
"The majority of improvement occurs in the first three months of treatment," Repka says. "I think the kids will still get better with ongoing treatment. We still see improvement six and 12 months out. We advise parents to continue patching as long as improvement continues."
These findings don't apply to lazy eye in children with more severe amblyopia. However, Repka and Lambert note that ongoing clinical trials are looking at ways to cut patch time for some of these kids, too.
It's important to diagnose lazy eye as soon as possible. Children learn to compensate for the unseeing eye, and sometimes don't even notice their vision loss. But Lambert says pediatric ophthalmologists have techniques for diagnosing the condition even in children who have not yet learned to talk. While it's better to begin treatment early than late, Lambert says that some kids benefit from treatment long after the age of 7.
"The upper age limit for patching is not known," Lambert tells WebMD. "After the age of 7, patching is less effective. But there is not a definite cutoff age. In another study, we are looking at patients age 7 to 18 to see how effective patching is. There is probably some group that responds when older, but not as readily and not with as much effect as seen in younger children."
The study findings appear in the May issue of the Archives of Ophthalmology.