Amblyopia, commonly known as 'lazy eye', is the loss or lack of development of central vision in one eye. The vision of one eye is reduced because it does not work properly with the brain, so one eye becomes favored over the other. Lazy eye is the most common cause of visual impairment in children, usually developing before the age of 6.

Various treatments are available to correct amblyopia, which can be detected at an annual comprehensive eye exam. Early diagnosis of amblyopia is important to increase the chance of a full recovery. The American Optometric Association recommends that children receive a comprehensive eye exam by 6 months of age and again at age 3.