What is Lazy Eye (Amblyopia)?

Lazy eye, known medically as amblyopia, is an eye condition in which vision of one of the eyes becomes abnormally reduced because the eye and the brain are not working together properly as they should, according to the National Eye Institute (NEI). Although the eye looks normal, vision problems occur because the brain is favoring the other eye.

The NEI states that amblyopia affects about 2 to 3 out of 100 children making it the most common cause of visual impairment in childhood. The Centers for Disease Control and Prevention (CDC) estimates that about 2%-3% of the population is suffering from the condition. If left untreated, the amblyopia can persist into adulthood and can lead to monocular visual impairment. Monocular means that one eye is involved.

Causes

Several eye impairments have been found to cause lazy eye including: strabismus, a condition that occurs when there is imbalance in the positioning of the eyes, possibly due to lack of coordination between muscles that move the eyes; one eye is either nearsighted, farsighted, or astigmatic; and rarely, it is caused by other eye problems such as cataract.

Diagnosis

The eye care professional can easily diagnose amblyopia by performing a thorough eye examination. Often, special diagnostic tests are not necessary.

Treatment

The goal of treatment is to increase the child's usage of the eye with weaker vision. This can be achieved by making use of an eye patch over the normal eye or using drops (Atropine) to temporarily blur the vision of the normal eye.

Patching

Wearing an opaque, adhesive eye patch over the normal eye for weeks to months is known to force the child to use the amblyopic eye, which the NEI says "helps the part of the brain that manages vision develop more completely." A nationwide clinical trial has shown that this therapy not only benefits younger children, but may also benefit children age 7 through 17.

Atropine

If the child does not want to wear an eye patch, the doctor may recommend application of a drug called atropine. A drop of the drug is applied on the stronger eye once a day, which temporarily blurs the normal eye vision. As a result, the child will then prefer to use the eye with amblyopia.

The drug can also stimulate vision in the weaker eye. In addition, the NEI says that it can help the brain part that controls vision to develop more completely.

Treating the underlying cause of amblyopia is also necessary. For example, if the child with lazy eye is either nearsighted or farsighted, the doctor may prescribe glasses or contact lenses.

Early diagnosis and treatment of amblyopia in children is important to prevent future permanent visual impairment. According to the National Library of Medicine (NLM), treatment of the condition before age 5 usually results in the child "having near complete recovery of normal vision."

Sources:

National Eye Institute. Facts About Amblyopia. http://www.nei.nih.gov/health/amblyopia/amblyopia_guide.asp. Accessed on October 21, 2010.

MedlinePlus, National Library of Medicine. Amblyopia. http://www.nlm.nih.gov/medlineplus/ency/article/001014.htm. Accessed on October 21, 2010.