Causes

Amblyopia can be caused by any condition that causes one eye to be favored, and the other ignored by the brain. Strabismus (crossed eyes), farsightedness, nearsightedness, and astigmatism in both eyes, and childhood cataracts are common causes of amblyopia.

The preferred eye becomes has normal vision. The non-favored eye is ignored by the brain to avoid a clash between the two different images from the eyes. As a result, the visual system in the brain for the non-favored eye does not develop properly. Between ages 5 and 10, the brain stops growing and the condition becomes permanent.

Some Major causes of Amblyopia :

 Strabismus. A misalignment of the eyes (strabismus) is the most common cause of functional amblyopia. The two eyes are looking in two different directions at the same time. The brain is sent two different images and this causes confusion. Images from the misaligned or "crossed" eye are turned off to avoid double vision.

  Anisometropia. This is another type of functional amblyopia. In this case, there is a difference of refractive states between the two eyes (in other words, a difference of prescriptions between the two eyes). For example, one eye may be more nearsighted than the other eye, or one eye may be farsighted and the other eye nearsighted. Because the brain cannot fuse the two dissimilar images, the brain will suppress the blurrier image, causing the eye to become amblyopic.

  Cataract. Clouding of the lens of the eye will cause the image to be blurrier than the other eye. The brain "prefers" the clearer image. The eye with the cataract may become amblyopic.

  Ptosis. This is the drooping of the upper eyelid. If light cannot enter the eye because of the drooping lid, the eye is essentially not being used. This can lead to amblyopia.

  Nutrition. A type of organic amblyopia in which nutritional deficiencies or chemical toxicity may result in amblyopia. Alcohol, tobacco, or a deficiency in the B vitamins may result in toxic amblyopia.

  Heredity. Amblyopia can run in families. Barring the presence of strabismus or ptosis, children may or may not show signs of amblyopia. Children may hold their heads at an angl e while trying to favor the eye with normal vision. They may have trouble seeing or reaching for things when approached from the side of the amblyopic eye. Parents should see if one side of approach is preferred by the child or infant. If an infant's good eye is covered, the child may cry.