Wednesday, May 7, 2014

Albinism and the Vision Problems

What is Albinism?



The word “albinism” refers to a group of inherited conditions. People with albinism have little or no pigment in their eyes, skin, or hair. They have inherited altered genes that do not make the usual amounts of a pigment called melanin. One person in 17,000 in the U.S.A. has some type of albinism. Albinism affects people from all races. Most children with albinism are born to parents who have normal hair and eye color for their ethnic backgrounds. Sometimes people do not recognize that they have albinism. A common myth is that people with albinism have red eyes. In fact there are different types of albinism and the amount of pigment in the eyes varies. Although some individuals with albinism have reddish or violet eyes, most have blue eyes. Some have hazel or brown eyes. However, all forms of albinism are associated with vision problems.

  1. Vision Problems 



    People with albinism always have problems with vision (not correctable with eyeglasses) and many have low vision. The degree of vision impairment varies with the different types of albinism and many people with albinism are “legally blind,” but most use their vision for many tasks including reading and do not use Braille. Some people with albinism have sufficient vision to drive a car. Vision problems in albinism result from abnormal development of the retina and abnormal patterns of nerve connections between the eye and the brain. It is the presence of these eye problems that defines the diagnosis of albinism. Therefore the main test for albinism is simply an eye examination.

    Vision Rehabilitation

    Eye problems in albinism result from abnormal development of the eye because of lack of pigment and often include:
    • Nystagmus: regular horizontal back and forth movement of the eyes
    • Strabismus: muscle imbalance of the eyes, “crossed eyes” (esotropia), “lazy eye” or an eye that deviates out (exotropia)
    • Photophobia: sensitivity to bright light and glare
    • People with albinism may be either far-sighted or near-sighted and usually have astigmatism
    • Foveal hypoplasia: the retina, the surface inside the eye that receives light, does not develop normally before birth and in infancy
    • Optic nerve misrouting: the nerve signals from the retina to the brain do not follow the usual nerve routes
    • The iris, the colored area in the center of the eye, has little to no pigment to screen out stray light coming into the eye. (Light normally enters the eye only through the pupil, the dark opening in the center of the iris, but in albinism light can pass through the iris as well.)
    For the most part, treatment of the eye conditions consists of visual rehabilitation. Surgery to correct strabismus may improve the appearance of the eyes. However, since surgery will not correct the misrouting of nerves from the eyes to the brain, surgery will not improve eyesight or fine binocular vision. In the case of esotropia or “crossed eyes,” surgery may help vision by expanding the visual field (the area that the eyes can see while looking at one point).
    People with albinism are sensitive to glare, but they do not prefer to be in the dark, and they need light to see just like anyone else. Sunglasses or tinted contact lenses help outdoors. Indoors, it is important to place lights for reading or close work over a shoulder rather than in front.
    Various optical aids are helpful to people with albinism and the choice of an optical aid depends on how a person uses his or her eyes in jobs, hobbies, or other usual activities. Some people do well using bifocals which have a strong reading lens, prescription reading glasses, or contact lenses. Others use hand-held magnifiers or special small telescopes and some prefer to use screen magnification products on computers.
    Some people with albinism use bioptics, glasses which have small telescopes mounted on, in, or behind their regular lenses, so that one can look through either the regular lens or the telescope. Newer designs of bioptics use smaller light-weight lenses. Some states allow the use of bioptic telescopes for driving.
    Optometrists or ophthalmologists who are experienced in working with low vision patients can recommend various optical aids. Clinics should provide aids on trial loan and provide instruction in their use. The American Foundation for the Blind maintains a directory of low vision clinics. In Canada, support is available from the Canadian National Institute for the Blind.


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