Commonly called a "lazy eye". Amblyopia is a decrease in the child’s vision that can occur even when there is no problem with the structure of the eye. It is a condition in which the vision in one or both eyes cannot be corrected to 20/20 even after the correct eyeglasses have been prescribed. In a child with normal visual development, the brain receives information from the right eye and information from the left eye and combines the two to see one clear picture. This "combining" of the information from the two eyes is called fusion.
Amblyopia occurs when the brain is unable to "fuse" the information coming from the right eye and left eye. When the brain is unable to fuse the information from the two eyes, it learns to ignore the information from one eye. This leads to lack of development of the vision in the eye that is not being used. Amblyopia is caused by a crossed eye or wall-eye condition or by unequal prescriptions in the two eyes. This decrease in vision results when one or both eyes send a blurry image to the brain. The eye that sees clearer becomes stronger and takes over the weaker eye. It is a condition only in young children and may be treated successfully if diagnosed early enough.