Amblyopia, commonly known as lazy eye, occurs when there is a lack of vision in one eye because the eye and the brain are not working together. The brain may start to ignore the image from the amblyopic eye. Amblyopia normally only affects one eye - resulting in the amblyopic eye pointing away from the other appearing "lazy". It is often associated with strabismus, or crossed eyes, when an individual’s eyes appear directed toward two different points instead of one.

Child with patch to help correct lazy eye or amblyopia

What Causes Lazy Eye?

Lazy may result from a strabismus (crossed-eyes), difference in nearsightedness or farsightedness between eyes, as well as other preexisting eye conditions, such as cataracts, ptosis (drooping of the upper eyelid), and refractive problems. Generally, when the eyes are not working together sending identical images to the brain. In cases of crossed eyes, there is one eye that is off-focus from the object the person is trying to see. The brain’s natural tendency is to ignore the off-focus image, leaving the eye that produces it underused and weak. After time, this weakened eye may remain out of position, resulting in lazy eye.

Symptoms of Lazy Eye

Amblyopia develops early, usually before age 6, and symptoms may not always be obvious. The earlier it is diagnosed and treated, the better. For this reason, it is recommended that children receive a full eye exam at six months, and again at three years. Symptoms of Lazy Eye include:

  • Eyes that point in different directions
  • Significant favoring of one eye
  • Poor depth perception
  • Poor vision in one eye

Treatment for Lazy Eye

With early diagnosis and treatment, improved sight in a lazy eye can be accomplished. However, in the worst cases, an untreated eye can be left functionally blind.

Treatments for lazy eye include:

  • Patching or covering the strong eye: this method forces the weaker eye to work harder, naturally strengthening its ability to move and focus
  • Contact lenses and eyeglasses: corrects the discrepancy of near- or farsightedness between the eyes
  • Surgery: Realigns muscles in the eyes, a more expensive and risky option than other forms of treatment

Additional Information

National Eye Institute, National Institutes of Health – Amblyopia Video

Amblyopia (Lazy Eye) – Prevent Blindness America

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