Amblyopia is when one eye is weaker than the other. Some people call this "lazy eye." It causes the brain to take in images from the stronger eye and ignore images from the weaker eye. This leads to poor vision in the weaker eye. It most often affects only one eye. Children can develop the problem between birth and about age 7.
Sometimes amblyopia occurs because the eyes don't focus on the same object. For example, one eye may point straight while the other looks in another direction. This condition is called strabismus. It sends two different images to the brain. In a young child with strabismus, the brain chooses to receive the images from only one eye.
Amblyopia can sometimes be treated if it is caught at a young age. Your doctor may want your child to wear a patch over the stronger eye. This helps develop the vision in the weaker eye. Or your doctor may suggest glasses or eyedrops to blur the vision in the stronger eye. This forces the brain to use the weaker eye to make it stronger.
Sometimes surgery is needed to fix both problems.