The study included 80 young children (average age: nearly 6) in London who had lazy eye.
The researchers, who included Merrick Moseley, BSc, PhD, of Canada's McGill University, wanted to see which eye patch "dose" was more effective.
The longer dose is often recommended. But many kids don't like wearing eye patches, so Moseley's team tested a shorter dose.
It turns out that both doses were equally effective -- and that most kids in both groups didn't wear their eye patches for the recommended amount of time anyway.
The eye patches used in the study had sensors that tracked how long the kids wore the eye patches. That gave the researchers hard data on whether the eye patches were actually being worn or languishing somewhere in the kids' home.
The kids got eye tests every two weeks after they started wearing the eye patches.
Only 23% of kids in the six-hour group and 7% of those in the 12-hour group came close to wearing their eye patches for the assigned amount of time.
So despite the study's ground rules, the kids effectively got the same "dose" from their eye patch treatment.
That may explain why both groups had the same amount of success with the eye patches, in terms of correcting their lazy eye. That may be a reality check about the practicality of asking little kids to wear eye patches for most of their waking hours.
The researchers recommend that children with lazy eye be asked to wear an eye patch for six hours per day.
The kids will likely wear their eye patch for an average of four hours per day, and their lazy eye will probably get stronger anyway, according to the study, published in BMJ Online First.