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:

Children with amblyopia may not notice their vision in one eye differs from the other or may be too young to describe symptoms. These children may squint, cover one eye, or have one eye that does not look in the same direction as the other, all of which may indicate a problem that requires examination. A complete cataract may cause a white pupil (leukocoria) that may be seen in photos, but a partial cataract may go unnoticed. Some older children may report impaired vision in the affected eye or exhibit poor depth perception. Often, however, children do not appear to have a problem. If one eye sees well and the other does not, children compensate well and do not seem to function differently from their peers.

To detect problems in visual development, vision screening for all children is done immediately after birth and is repeated at well-child examinations Preventive Health Care Visits in Children Scheduled visits to the doctor (also called well-child visits) provide parents with information about their child's growth and development. Such visits also give parents an opportunity to ask... read more throughout childhood. In some areas, preschool children are screened by volunteers and local and regional agencies. If a child is not able to do a vision test with an eye chart that has pictures, figures, or letters by 3 or 4 years of age, the child should be evaluated by an eye care specialist.

Once children reach school age, screening is also done in school by health care practitioners. If a problem is found during screening, the child should see an eye doctor, either an ophthalmologist (a medical doctor who specializes in the evaluation and treatment of all types of eye disorders) or an optometrist (a health care practitioner who specializes in the diagnosis and treatment of vision or refractive problems).

The sooner amblyopia or risk factors for amblyopia are detected, the more likely amblyopia can be prevented or corrected. Amblyopia may result in permanent vision loss if not diagnosed and treated early in childhood, at which time the visual system has often matured. Early diagnosis and treatment increase the likelihood that vision will be completely recovered. In certain circumstances, older children with amblyopia can still have vision improvement with treatment. Failure to effectively treat amblyopia may result in permanent visual impairment in the affected eye. For these reasons, vision screening programs for children should be supported by the community.

To treat amblyopia, doctors first correct refractive errors by having the child wear eyeglasses Eyeglasses Refractive errors can be corrected with glass or plastic lenses mounted in a frame (eyeglasses) or with a small lens made of plastic floating or resting on the cornea (contact lens). Good vision... read more or contact lenses Contact Lenses Refractive errors can be corrected with glass or plastic lenses mounted in a frame (eyeglasses) or with a small lens made of plastic floating or resting on the cornea (contact lens). Good vision... read more and remove any cataracts. Once vision cannot be further improved with eyeglasses or contact lenses, doctors force the child to use the weaker eye by putting a patch over the better eye (patching) or using eye drops to blur the vision in the better eye. Patching or using eye drops in the better eye allows the weaker eye to get stronger.

If strabismus is the cause, doctors first try to equalize vision with patching or eye drops before correcting the strabismus Treatment Strabismus is an intermittent or constant misalignment of an eye so that its line of vision is not pointed at the same object as the other eye. If untreated, strabismus can cause amblyopia ... read more with surgery.

The following is an English-language resource that may be useful. Please note that THE MANUAL is not responsible for the content of this resource.