What is Amblyopia?
Amblyopia is poor vision in an eye that did not develop normal sight during early childhood. It is sometimes called lazy eye.
When one eye develops good vision while the other does not, the eye with the poorer vision is called amblyopic. Usually, only one eye is affected by amblyopia, but it is possible for both eyes to be lazy.
The condition is common; approximately two or three out of every 100 people has amblyopia. The best time to correct amblyopia is during infancy or early childhood.
How does normal vision develop?
Newborn infants are able to see, but as they use their eyes during the first months of life, their vision improves. During early childhood years, their visual system changes quickly and their sight continues to develop.
If a child cannot use his or her eyes normally, vision does not develop properly and may even decrease. After the first nine years of life, the visual system is normally fully developed and usually cannot be changed.
In order to have normal vision, it is important that both eyes develop equal vision.
People with amblyopia in one eye are more than twice as likely to lose vision in the healthy eye from trauma. If the vision in one eye should be lost later in life from an accident or illness, it is essential that the other eye have normal vision. For these reasons, amblyopia must be detected and treated as early as possible.
When should vision be tested?
In addition to the well-baby exams that all babies should have as newborns and between ages 6 to 12 months, preschool-aged children should have eye exams between 3 and 4 years old.
Most doctors test vision as part of a child’s medical examination. They may refer a child to an ophthalmologist (Eye M.D.) if there is any sign of eye problems.
If there is a family history of misaligned eyes, childhood cataracts or a serious eye disease, an ophthalmologist should examine the eyes during infancy.
How is amblyopia treated?
To correct amblyopia, a child must be made to use the weak eye. This is usually done by covering or blurring the strong eye, often for weeks or months. Even after vision has been restored in the weaker eye, it may be necessary to continue patching the other eye part-time for a few more years to maintain the improvement.
Eyeglasses may be prescribed to correct focusing problems. If glasses alone do not improve vision, then patching is needed.
Amblyopia may also be treated by blurring the vision in the strong eye with special eyedrops or lenses to force the child to use the amblyopic eye.
Amblyopia is usually treated before surgery to correct misaligned eyes, and patching or blurring with eyedrops is often continued after surgery as well.
If your ophthalmologist finds a cataract or other problem in the eye, surgery may be required. An intraocular lens may be implanted. After surgery, eyeglasses or contact lenses can be used to restore focusing while patching improves vision.
Amblyopia usually cannot be cured by treating the cause alone. The weaker eye must be made stronger in order to see normally. Prescribing eyeglasses or performing surgery can correct the cause of amblyopia, but your ophthalmologist must also treat the amblyopia itself.
Why treat amblyopia?
If amblyopia is not treated, several problems may occur:
- The amblyopic eye may develop a serious and permanent visual defect;
- Depth perception (seeing in three dimensions) may be lost, because good vision in both eyes is needed;
- If the stronger eye becomes diseased or injured, a lifetime of poor vision may result.
People who have good vision in only one eye may find they are limited in the kinds of jobs they can perform. Your ophthalmologist can teach you how amblyopia can be treated, and can help you and your child successfully carry out this treatment.
Children do not like to have their strong eye patched or blurred. As a parent, however, you should help your child to do what is best for him or her. Your interest, involvement and persistence is the key to ensuring your child’s amblyopia treatment succeeds.
Loss of vision is preventable
Success in the treatment of amblyopia also depends upon:
- How severe the amblyopia is; and
- How old the child is when treatment is begun.
If the problem is found and treated early, vision can improve for most children. Amblyopia caused by strabismus or unequal refractive errors may be treated successfully during the first nine years of age, and usually won’t occur again.
If amblyopia is not detected until after early childhood, treatment may not be successful. Amblyopia caused by cloudiness of the eye tissue needs to be found and treated extremely early — within the first few months of life — in order to be treated successfully.
