Types of Amblyopia

Amblyopia, or lazy eye, is an eye disorder where there is poor or indistinct vision in one eye because the brain lacks proper transmission of visual image in that eye. There are three types of amblyopia which can become permanent between the ages of 5 and 10 when the brain stops developing. Common symptoms of amblyopia include the eyes turning in or out or appearing not work in coordination and the inability to evaluate depth correctly. Treatment options are available in early stages that can potentially aid correction of amblyopia.

Types

• There are three types of amblyopia, the most common of which is strabismus. Strabismus is where the eyes are not properly aligned together or are crossed, commonly referred to as "cross-eyed."

  A second type of amblyopia is anisometropia. Anisometropia is a condition where the eyes have differing refractive power. In other words, one eye may be nearsighted and the other farsighted. Amblyopia occurs because the brain cannot coordinate the differing sight ranges and so chooses one eye to display vision clearly. To an outsider, the eyes appear normal, but since the brain is transmitting vision to only one eye, the other has poor vision.

  A third type of amblyopia is any eye disease or injury that prevents transmission of a clear image from within the eye. An example is cataracts, which causes the eye lens to become cloudy.

Detection

• Ambylopia is not easily detected, unless the eye is misaligned like in the case of strabismus. Children born with a type of amblyopia, other than strabismus, are usually unaware that they have a situation where one eye has poor vision because their sight has been that way since birth. In situations where a child may squint or close one eye, there is indication of a visual problem.

  You should schedule your child for an eye exam as early as the age of 4 to detect any type of amblyopia. If you have a family history of amblyopia, schedule an eye exam before your child is 4 years old.

Signs and Symptoms

• Amblyopia does not cause any readily noticeable symptoms other than complaints of headaches or eyestrain. Other than in the case of strabismus, there are no other indicative signs of amblyopia. Only when a child squints or closes one eye to see clearly is there an indication that there is a visual problem.

Treatment

• Treating amblyopia involves forcing the brain to use the non dominant eye. Treating amblyopia before a child reaches 2 years of age provides the best chances for vision correction. Thereafter, intermittent treatment may be necessary until about 9 years of age to permanently correct amblyopia.

  One treatment option involves placing a patch over the normal functioning eye to force the use of the eye with poor vision. The patch is kept on the eye for most of the day for several weeks or months. To maintain vision even after restoration, intermittent placement of the patch may be necessary. Alternatively, eyedrops that blur the vision in the normal eye can be used to force the lazy eye to transmit a clear visual image.

  In cases where a cataract causes amblyopia, the cloudy lens is surgically removed before the patch method is used. In addition to wearing the patch to correct vision, the patient may be prescribed eyeglasses or contact lenses to restore focusing.

  To correct strabismus, surgery is performed on the eye muscle to force the eyes to align properly. Cosmetic surgery is available for strabismus where externally the eyes look aligned, but in actuality are not and require further treatment. Surgery in early stages is often recommended so that infants can develop normal eyesight as their brain matures.

  If ambylopia is caused by a visual imbalance, eyeglasses or contact lenses are prescribed to correct vision.

  Vision therapy involves exercises that train the brain to use the lazy eye and force both eyes to work in coordination.

Prevalence

• Approximately 5 percent of the children in the United States suffer from amblyopia.

Prevention/Solution

• Since amblyopia can become permanent between the ages of 5 and 10 when the brain stops developing, an eye exam is recommended as early as 3 to 6 months of age and then every six months thereafter. A visual disorder detected early, such as strabismus, can then be corrected.