Amblyopia

Amblyopia is a condition where vision is poor in one eye. Amblyopia is a development problem in the part of the brain that receives the visual nerve impulses from the eye. It is not a problem with the eye itself. The term "lazy eye" developed because amblyopia is sometimes related to an eye wandering inward or outward, suggesting "laziness" of the eye muscles.

This condition is the most common cause of visual impairment in childhood. During the early years of childhood, the brain's ability to interpret visual nerve impulses is always developing. This is true for each eye on its own, as well as for how the eyes work together (binocular vision). Unless it is treated in early childhood, amblyopia usually continues into adulthood. It is the most common cause of one eye (monocular) visual impairment. If this disorder is found early enough, it can be treated to improve vision.

CAUSES

Amblyopia may develop if:

  • Something affects how the eyes work together. For example:

  • The brain is presented with two images and quickly learns to ignore one of them, to avoid double vision (diplopia).

  • Some muscles in one eye are weak. The eyes may not move together (strabismus).

Some more common causes are:

  • Any condition that affects normal visual development or use of the eyes.

  • One eye which is more nearsighted, farsighted, or has an irregular curve of the surface of the cornea, the clear cover at the front of the eye (astigmatism).

  • Cataract or other diseases of the eye.

SYMPTOMS

  • Poor vision in one eye.

  • Poor ability to judge the distance between objects (depth perception).

  • In children and infants, an eye may be crossed or turned in, out, or up.

  • One eye may drift in a direction away from that of the other eye. The drifting eye will recover its position right away (phoria).

DIAGNOSIS

Trained eye professionals (optometrists, ophthalmologists) can diagnose strabismus, eye diseases that might cause amblyopia, and the need for glasses (refractive error) by doing an eye exam.

TREATMENT

  • Your eye specialist may refer you to an orthoptist (expert in eye muscle exercises).

  • Your child may wear an eye patch at times, to stimulate vision equally in both eyes.

  • Eye drops may be given at times, to blur the vision in the better eye.

  • Glasses may be needed. They will be prescribed for children as young as 1 year of age.

  • Surgery may be needed on the muscles, to align the eyes. It is usually done under general anesthesia, as early in life as possible after 1 year of age. The earlier the eyes become aligned, the less likelihood there is of amblyopia developing.

The longer one waits to treat this condition, the less chance there is of restoring vision to the affected eye. This condition is usually not treatable after the age of 10. Any treatment with patching, exercises, or surgery after this age is usually cosmetic, and is not likely to improve vision.

SEEK MEDICAL CARE IF:

  • You notice that an infant or child's eyes do not seem to be looking in the same direction.

  • A child does not seem to see as well with one eye as with the other.

  • You notice your child has poor depth perception.