Lazy eye, also called amblyopia, is an eye problem that can occur in growing children. In the typical child with lazy eye, the right and left eyes have significantly different qualities of vision, so that the images produced by one eye are weak or distorted compared with the images produced by the other eye. Because the weak eye sends poorly focused images to the brain, the brain learns to depend on the stronger eye for its visual information. If this situation is not corrected, the brain eventually chooses to accept images from the stronger eye alone and ignores images from the weak one. In other words, the weak eye doesn't learn to see.
The brain's choice usually is made early in childhood when the brain's visual pathways are still developing. This critical period begins at birth and probably ends sometime between ages 6 and 9. If lazy eye is not diagnosed and treated within this critical period, the brain may choose to ignore the weak eye permanently, causing a lifelong loss of vision on that side.
Lazy eye has several causes, including:
In the United States, lazy eye affects an estimated 1% to 2% of the population. In rare cases, the brain ignores both eyes because both produce blurry images. This can cause permanent blindness in both eyes.
Lazy eye usually does not cause any symptoms. Sometimes parents suspect vision problems because a child squints, looks cross-eyed, or holds his or her head in awkward positions to see things. In many cases, the problem is detected by a routine vision screening exam, either before or after a child starts school. The screening exam will show that the child's vision is much better in one eye than the other.
If the results of a screening exam suggest that your child has lazy eye, your primary care doctor will refer you to an ophthalmologist, a doctor who specializes in eye disorders. The ophthalmologist will confirm the diagnosis by doing a thorough eye examination, including separate tests of how well each eye sees. As part of the diagnostic process, the ophthalmologist will inspect your child's eyes for structural abnormalities, check eye alignment to rule out crossed eyes, and assess movement of the eye muscles.
Lazy eye begins early in childhood. It should be treated as soon as possible. Without proper treatment, the condition can produce profound loss of vision that lasts a lifetime.
To prevent permanent loss of vision in a weak eye, the causes of lazy eye must be identified and treated as early as possible during childhood. Make sure your newborn receives a thorough eye exam within the first few days after delivery. This exam will check for any obvious abnormalities involving the structure of your child's eyes or eyelids. As your child grows, a doctor should check your child's eyes as a part of every "well-child" visit. Your child should have more formal vision testing, using pictures, letters or numbers, beginning no later than age 3, and at regular intervals after that. There are now techniques that allow detection of amblyopia even when the infant is pre-verbal.
Treatment of lazy eye has two goals:
Make an appointment to see your pediatrician or ophthalmologist if your child:
Also, make an appointment if your child's school notifies you that your child's vision exam was abnormal.
The outlook is good if the condition is treated early. Proper treatment during early childhood often produces near normal vision in the affected eye.
In the past, some doctors have offered a poor prognosis for treating lazy eye in children over age 12, or even younger. However, new evidence suggests that the outlook for lazy eye may be improved with prompt, appropriate treatment regardless of the age at which it is diagnosed. There have been cases in which teenagers and even middle-aged adults with lazy eye have recovered vision in the weak eye.
National Eye Institute
2020 Vision Place
Bethesda, MD 20892-3655
American Academy of Ophthalmology
P.O. Box 7424
San Francisco, CA 94120
American Academy of Pediatrics (AAP)
141 Northwest Point Blvd.
Elk Grove Village, IL 60007-1098