Normally we have two eyes that are meant to see the world equally.
When one or both eyes have decreased sharpness of vision that is not correctable by spectacles and in the absence of other diseases, this is known as amblyopia, or lazy eye.
The amblyopic eye will see images as blurry. As a result, the brain ignores (suppresses) images sent by this eye and favours images sent by the unaffected eye. Since the ignored eye is not fully participating in the seeing process, it is called “lazy.”
Amblyopia is a vision development disorder that is sometimes combined with strabismus, or misalignment of the eye.
When the eyes are misaligned, the brain receives two images—one from the straight eye and one from the turned eye. This causes double vision. The brain gets confused and will choose to ignore images from the affected eye, which may cause amblyopia.
Other causes of amblyopia: