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Retinitis
pigmentosa is a rare, progressive degeneration of the retina that
eventually causes moderate to severe vision loss.
Retinitis pigmentosa is often inherited. One form has a dominant pattern of inheritance, requiring only one abnormal gene from either parent. Other forms are recessive and require an abnormal gene from both parents. An X-linked recessive form occurs mainly in males who inherit one abnormal gene from their mother. In some people, mostly males, hearing loss may also be inherited (a disorder called Usher's syndrome).
The photoreceptors (light-sensing cells) of the retina that are responsible for vision when light is low (rods) gradually degenerate, so that vision becomes poor in the dark. The first symptoms often begin in early childhood. Over time, peripheral vision progressively deteriorates. In the late stages of the disease, the person typically has only a small area of central vision and possibly some peripheral vision remaining (tunnel vision).
When examining the retina with an ophthalmoscope, doctors see specific changes that suggest the diagnosis. Tests such as the electroretinogram, which evaluates the electrical response of the retina to light, may help to confirm the diagnosis.
Family members should be examined so that the inheritance pattern can be determined if possible. If the disorder is present in other family members, genetic counseling should be considered before having children.
No conventional treatment can reverse retinal damage. Vitamin A is recommended by some doctors in an attempt to slow the progression of the disorder. Gene therapy and implantable cells that make a compound to nourish the retina are under investigation.
Last full review/revision November 2008 by Sunir J. Garg, MD
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