What is amblyopia?

Amblyopia is the term eye doctors use for reduced vision in one eye that is caused by problems with the way the eye and the brain work together. This condition is sometimes called “lazy eye.”

The brain and the eye work together to produce vision. The eye changes the light that hits it into nerve signals. These signals travel along the optic nerve to the brain. In amblyopia, the brain favors signals from one eye over the other. The eye with amblyopia looks normal, but it is not working normally because the brain is favoring the other eye.

How common is amblyopia?

Amblyopia is the most common cause of vision problems in children. The condition affects about 2 to 3 out of every 100 children. Without successful treatment in early childhood, amblyopia usually persists into adulthood. Amblyopia is the most common cause of monocular (one eye) vision problems among children and young to middle-aged adults.

What causes amblyopia?

Amblyopia may be caused by any condition that affects normal visual development or use of the eyes. Amblyopia can be caused by strabismus, an imbalance in the positioning of the two eyes. Strabismus can cause the eyes to cross in (esotropia) or turn out (exotropia). Sometimes amblyopia is caused when one eye is more nearsighted, farsighted, or astigmatic than the other eye. Occasionally, amblyopia is caused by other eye conditions such as cataract.

How is amblyopia treated in children?

Treatment involves having the child use the eye with reduced vision (the weaker eye), so that vision can become stronger in the weaker eye and the part of the brain that manages vision can develop more completely. Doctors can do this in two ways:

  • Medication - A drop of a drug called atropine is placed in the stronger eye once a day to temporarily blur the vision so that the brain will favor the eye with amblyopia.
  • Patching – For this treatment, an opaque, adhesive patch is worn over the stronger eye for different amounts of time each day in order to force the child to use the eye with amblyopia.  The child will do this until the vision in his or her weaker eye improves.

Eye doctors used to think that treating amblyopia in older children would be of little benefit. However, research has since shown that treatments for younger children might also help children age 7 through 17 with amblyopia. This shows that age alone should not decide whether a child should get treatment for amblyopia.

Can amblyopia be treated in adults?

Research is currently limited and scientists don’t know how successful treatments would be for amblyopia in adults. During the first six to nine years of life, the visual system develops very rapidly, and complicated connections between the eye and the brain are created. Scientists are still studying whether treatment for amblyopia in adults would be able to improve vision.