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Amblyopia, commonly known as lazy eye, is the eye condition noted by reduced vision not correctable by glasses or contact lenses and is not due to any eye disease. The brain, for some reason, does not fully acknowledge the images seen by the amblyopic eye. This almost always affects only one eye but may manifest with reduction of vision in both eyes. It is estimated that three percent of children under six have some form of amblyopia.

Alternative Names of Amblyopia are: Lazy eye.

Complications of Amblyopia

Left untreated, lazy eye can cause permanent vision loss. In fact, lazy eye is the most common cause of single-eye vision impairment in young and middle-aged adults, according to the National Eye Institute.

Causes of Amblyopia

Anything that interferes with clear vision in either eye during the critical period (birth to 6 years of age) can cause amblyopia. The most common causes of amblyopia are constant strabismus (constant turn of one eye), anisometropia (different vision/prescriptions in each eye), and/or blockage of an eye due to cataract, trauma, lid droop, etc. Amblyopia is a neurologically active process. In other words, the loss of vision takes place in the brain. If one eye sees clearly and the other sees a blur, the brain can inhibit (block, ignore, suppress) the eye with the blur. The brain can also suppress one eye to avoid double vision. The inhibition process (suppression) can result in a permanent decrease in the vision in the blurry eye that cannot be corrected with glasses, lenses, or lasik surgery.

Signs & Symptoms of Amblyopia

Signs and symptoms of lazy eye include:

  • An eye that wanders inward or outward
  • Eyes that may not appear to work together
  • Poor depth perception

Although lazy eye usually affects just one eye, it's possible for both eyes to be affected.

Diagnosis of Amblyopia

An eye exam by a pediatrician or the 20/20 eye chart screening is not adequate for the detection of amblyopia (and other visual conditions). The most important diagnostic tools are the special visual acuity tests other than the 20/20 letter charts currently used by schools, pediatricians and eye doctors. Examination with cycloplegic drops can be necessary to detect this condition in the young. Since amblyopia usually occurs in one eye only, many parents and children are unaware of the condition. Many children go undiagnosed until they have their eyes examined at the eye doctor's office at a later age. Comprehensive vision evaluations are highly recommended for infants and pre-school children.

Treatments of Amblyopia

Ideally, lazy eye treatment begins in early childhood — when the complicated connections between the eye and the brain are forming. Depending on the cause and the degree to which your child's vision is affected, treatment options may include:

  • Corrective eyewear. If a condition such as nearsightedness, farsightedness or astigmatism is contributing to lazy eye, corrective glasses or contact lenses will likely be prescribed. Sometimes corrective eyewear is all that's needed.
  • Eye patches. To stimulate the weaker eye, your child may wear an eye patch over the stronger eye — possibly for two or more hours a day depending on the severity of the lazy eye. This helps the part of the brain that manages vision develop more completely.
  • Eyedrops. A daily or twice weekly drop of a drug called atropine can temporarily blur vision in the stronger eye. This will encourage use of the weaker eye, and offers an alternative to wearing a patch.
  • Surgery. If your child has crossed or outwardly deviating eyes, the eye muscles may benefit from surgical repair. Droopy eyelids or cataracts may also need surgical intervention.

For most children with lazy eye, proper treatment improves vision within weeks to several months — and the earlier treatment begins the better. Although research suggests that the treatment window extends through at least age 17, results are better when treatment begins in early childhood.

Prevention of Amblyopia

Early recognition and treatment of the problem in children can help to prevent permanent visual loss. All children should have a complete eye examination at least once between ages 3 and 5.

When to seek Medical Advice

Vision checks are often a routine part of well-child checkups — especially if there's a family history of crossed eyes, childhood cataracts or other eye conditions. For all children, a complete eye exam is usually recommended between ages 3 and 5. If you notice your child's eye wandering at any time beyond the first few weeks of life, consult your child's doctor for an evaluation. Depending on the circumstances, he or she may refer your child to a doctor who specializes in eye conditions (ophthalmologist).

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