children s health issues
Amblyopia
Causes of Amblyopia
A child's visual pathways are not fully developed at birth. The vision system and the brain need to be stimulated by clear, focused, properly aligned, overlapping images from both eyes in order to develop normally. This development takes place mainly in the first 3 years of life but is not complete until about 8 years of age. If the brain does not receive proper visual stimulation from an eye during the development period, it learns to ignore (suppress) the image from that eye, resulting in vision loss. If the suppression lasts long enough, vision loss can be permanent. This permanent loss of vision is called amblyopia. There are several reasons for lack of proper visual stimulation, each of which can cause a type of amblyopia: Misalignment of the eyes (strabismus) Focusing problems (refractive errors) Blockage of vision Misalignment of the eyes ( Strabismus ) can cause amblyopia. The eyes produce two images—one from each eye—that normally are fused or united into a single image in the brain and then integrated to produce three-dimensional images and high levels of depth perception. The ability to fuse images develops during early childhood. If the two images are so misaligned that they cannot be fused together, the brain suppresses an image, ignoring the input from that eye. The brain is unaware of the image from the affected eye even though the eye may be structurally normal. In adults, because the visual pathways are already developed, seeing two different images results in Amblyopia may be caused by an unequal Refractive Disorders in Children , usually farsightedness (inability to see close objects clearly), nearsightedness (inability to see distant objects clearly), or astigmatism (an irregular curvature of the focusing surfaces of the eye). A refractive error causes blurring of the image or images reaching the brain, which results in a large difference in focus between the two eyes. These errors can develop in one or both eyes. A third type of amblyopia develops when a clouding or opacity of the lens of the eye (such as from a Congenital Cataract ) or of the cornea reduces or distorts the light entering an eye or when another cause (such as Sometimes a teacher or school nurse is the first to notice a child has an eye disorder. 