Lazy eye is reduced vision that happens when an eye does not develop normal sight during early childhood. It is also called amblyopia.
Normally, a newborn baby's vision is blurred. It improves as the baby gets older and uses her eyes. Both eyes work together (called binocular vision) and send pictures to the brain. The brain blends the two pictures into a single, clear picture. If pictures from each eye are different, or if one is blurry, the brain ignores the picture from one eye to avoid confusion. This may mean that normal vision does not develop in the eye that the brain ignores. After some time, this condition may become permanent.
The images from the eyes may be different due to:
If this problem is found and treated when the child is young, both eyes may develop normal vision and work together. It is best to treat children before the age of 6. After the age of 8 years, the visual system is usually fully developed and treatment for amblyopia is less successful. However, even older children may benefit from treatment.
Babies often do not show any symptoms of amblyopia. However, they may have trouble following an object with their eyes or may have crossed eyes. Toddlers may favor one eye. They may get fussy when the good eye is covered but not the other. Older children may complain of eye pain, watery eyes, or headaches. If you suspect that there is something wrong with your child's eyes at any age, talk to your healthcare provider. Most of the time, amblyopia is found during a vision exam at school or by a pediatrician.
In an older person, amblyopia is often suspected when eyeglasses do not correct vision problems.
A healthcare provider or preschool staff member may suggest that a child needs a complete eye exam. An eye care provider can diagnose amblyopia by watching how a baby or child follows objects with his eyes or by watching the baby’s movements when one eye is covered.
If an adult's vision cannot be corrected to 20/20 with glasses and if a thorough exam reveals no other cause for impaired vision, he or she may have amblyopia.
Treatment in children usually starts by putting a patch over the eye that has better vision. Patching forces the brain to use the weaker or "lazy" eye. Some providers prescribe eyedrops to blur the "good" eye instead of putting a patch on it. The eye care provider also treats the problem that led to the amblyopia. Glasses can help correct nearsightedness, farsightedness, or astigmatism. Crossed eyes may require eye muscle surgery, glasses, or both.
There is no treatment for amblyopia in adults.
If amblyopia is found early and treated properly, a child can develop normal vision. If treatment does not take place early, glasses may provide good vision. However, the lazy eye may never see as well as the stronger eye and the eyes may not work together.
Most people can work and play well with one lazy eye. For example, Babe Ruth had amblyopia. However, airline pilots and interstate truck drivers, for example, are required by law to have good vision in both eyes. Always wear eye protection and shatterproof glasses.