Amblyopia in Children: What It Is and How It Is Treated

Amblyopia (say this: "am-blee-oh-pee-ah") is an eye problem that causes poor vision in children. It’s also called “lazy eye.” Amblyopia usually affects one of the eyes, but sometimes it can also reduce vision in both eyes. The problem starts when the pathways that carry vision messages from one of the eyes to the brain don't grow strong enough. The brain then favors the other eye, and the child’s vision does not develop normally. Amblyopia is the most common cause of vision problems in children.

All babies are born with poor eyesight. As babies grow, their eyesight gets better. Good eyesight needs a clear, focused image that is the same in both eyes. If the image isn't clear in one eye, or if the image isn't the same in both eyes, the vision pathways don’t develop right. In fact, the pathways may actually get worse.

Anything that happens to blur the vision or cause the eyes to be crossed during childhood may cause amblyopia. For example, the image might be different in both eyes if the child has strabismus. Strabismus (also called "crossed eyes") causes the eyes to not focus in the same direction. Children who need glasses to see better, or have cataracts, a droopy eyelid, or crossed or wandering eyes may also get amblyopia.

Because there are several causes of amblyopia, the treatment must match the problem. Glasses or contact lenses fix some problems. Surgery may be needed for cataracts, droopy eyelids or crossed eyes. After the cause of the amblyopia is found, the child will need to use the weaker eye most of the time, so it will get stronger. To make the child use the weaker eye, a patch can be put over the stronger eye. Sometimes, eye drops or special glasses are used to blur the vision in the stronger eye. This makes the weaker eye become stronger. Patches may be used all day or part of the day, depending on the child's age and vision.

The treatment usually lasts until vision is normal, or until vision stops getting better. For most children, this takes several weeks. A few children need to use eye patches until they are 8 to 10 years old.

The vision pathways in the brain must become strong early, when children are very young. The first few years of life are the most important for eyesight. After a child is 8 to 10, the brain's vision system is complete. It can't develop anymore. If the amblyopia hasn't been treated by this age, the child will have poor vision for life. It won't be possible to fix it with glasses, patching or any other treatment.

There's a small chance that using an eye patch for too long can hurt the strong eye. For this reason, children who are wearing eye patches should see their doctor often during the treatment.