What is Amblyopia?
Amblyopia is a fairly common eye disorder. It is a significant cause of vision loss in children. It is the loss of vision in one or both eyes in the crucial early development years. It is the result of an ocular problem or disease affecting the visual pathway with abnormal development of the visual center in the occipital lobes of the brain. Many people refer to this as lazy eye. There are four common types of amblyopia:
Amblyopia Secondary to Strabismus
This is when the eyes are turned in or out. The brain fails to develop vision in one eye as not to see double.
Amblyopia Secondary to Anisometropia
Anisometropia is the condition when one eye has a significantly different refractive error from the other eye. When one is seeing clear the other eye is blurred and therefore the brain never develops clear vision in one eye.
Amblyopia Secondary to Deprivation
This due to an eye disease that blocks the path of light to the retina which results in the eye not seeing clearly and therefore the brain never develops clear vision in that eye. Examples would be congenital cataracts, corneal diseases, or other ocular diseases.
Amblyopia Secondary to High Refractive Error
People with very large amounts of refractive errors such as myopia, hyperopia, and astigmatism have difficulty with aberration in their vision with decreases the quality of the image focused on the retina.
Incidence of Amblyopia
Amblyopia occurs in nearly 5 % of children. It is usually unilateral but bilateral cases do occasionally happen.
Clinical and Pathophysiology Aspects of Amblyopia
Amblyopia tends to run in families as there are genetic components involved. In the few cases of bilateral amblyopia, the focus should be on eye diseases such as cataracts and corneal diseases. Unilateral amblyopia tends to be secondary to strabismus or anisometropia.
The loss of normal visual stimulation to the brain during formative years up to age 6 or 7 causes damage to the cells in the cortex of the brain. There is loss of cells and cross-linking of cells. The vision system needs to be repaired by age 6 in order for the brain to correct the amblyopia.
Diagnosis of Amblyopia
Amblyopia should be considered if the child has crossed eyes or if there is any ocular disease that may have amblyopia associated with it. Children with amblyopia may complain of their vision or have poor depth perception or clumsiness. Many times they have no complaints or symptoms. The pediatrician will check their eyes and vision during their visits. The child should have an eye exam around age 4 by an eye doctor to make sure the eyes are normal. The sooner amblyopia is found the better the outcome.
Treatment of Amblyopia
Treatment involves fixing the underlying cause of the amblyopia and then helping the amblyopic eye improve its vision.