Amblyopia is the name for diminished vision in one or both eyes, usually without any obvious defect. Amblyopia is not the same as nearsightedness, farsightedness, or astigmatism, which can be corrected with eyeglasses or contact lenses.

There are two main types of amblyopia: "lazy eye" amblyopia, and toxic amblyopia.

Lazy eye amblyopia occurs frequently in young children whose eyes do not line up correctly - a condition known as strabismus. To prevent double vision (in which the patient sees two...