Amblyopia: etiology, diagnosis, and treatment. American Academy of Ophthalmology.

1. Sometimes called "lazy eye," amblyopia is poor vision in an eye that did not develop normal sight during early childhood. Amblyopia is common, affecting approximately 2 or 3 out of every 100 people. The best time to correct amblyopia is during infancy or early childhood. 2. Amblyopia has three major causes: strabismus (misaligned eyes), unequal focus (refractive error), and cloudiness in the normally clear eye tissues. 3. To correct amblyopia, a child must be made to use the weak eye. This is usually done by patching or covering the strong eye. Amblyopia cannot be cured by treating the cause alone; the weaker eye must be made stronger in order to see normally.