Amblyopia (Lazy Eye)
Amblyopia, also known as lazy eye, affects just two to three percent of the population. But, if left uncorrected, this vision problem can have a very big impact on those affected. Central vision fails to develop properly, usually in one eye, which is called amblyopic. A related condition, strabismus, sometimes causes amblyopia.
Untreated amblyopia may lead to functional blindness in the affected eye. Although the amblyopic eye has the capability to see, the brain "turns off" this eye because vision is very blurred. The brain elects to see only with the stronger eye.
Amblyopia Symptoms and Signs
Amblyopia generally develops in young children, before age six. Its symptoms often are noted by parents, caregivers or health-care professionals. If a child squints or completely closes one eye to see, he or she may have amblyopia. Other signs include overall poor visual acuity, eyestrain and headaches.
What Causes Amblyopia?
Trauma to the eye at any age can cause amblyopia, as well as a strong uncorrected refractive error (nearsightedness or farsightedness) or strabismus. It's important to correct amblyopia as early as possible, before the brain learns to entirely ignore vision in the affected eye.
Amblyopia Treatment
Amblyopic children can be treated with vision therapy (which often includes patching one eye), atropine eye drops, the correct prescription for nearsightedness or farsightedness, or surgery.
Vision therapy exercises the eyes and helps both eyes work as a team. Vision therapy for someone with amblyopia forces the brain to see through the amblyopic eye, thus restoring vision.
Sometimes the eye doctor or vision therapist will place a patch over the stronger eye to force the weaker eye to learn to see. Patching may be required for several hours each day or even all day long, and may continue for weeks or months. If you have a lot of trouble with your child taking the patch off, you might consider a prosthetic contact lens that is specially designed to block vision in one eye but is colored to closely match the other eye. [Read more about prosthetic contact lenses.]
In some children, atropine eye drops have been used to treat amblyopia instead of patching. One drop is placed in your child's good eye each day (your eye doctor will instruct you). Atropine blurs vision in the good eye, which forces your child to use the eye with amblyopia more, to strengthen it. One advantage is that it doesn't require your constant vigilance to make sure your child wears the patch.
Recently a study* compared atropine therapy with patching in 419 children age 3 to almost 7 and found it an effective alternative. As a result, some previously skeptical eye care practitioners are using atropine as their first choice over patching.**
However, atropine does have side effects that should be considered: light sensitivity (because the eye is constantly dilated), flushing, and possible paralysis of the ciliary muscle after long-term atropine use, which could affect the eye's accommodation, or ability to change focus.
If your child has become amblyopic due to a strong uncorrected refractive error or a large difference between the refractive errors of both eyes, amblyopia can be treated with eyeglasses or contact lenses in the correct prescription. Your eye care practitioner may prescribe an eye patch along with the new glasses or contact lenses.
Surgery is best for amblyopic children with an underlying physical problem, such as strabismus. The surgery corrects the muscle problem that causes strabismus so the eyes can focus together and see properly.
