Retinitis Pigmentosa
Retinitis pigmentosa is a rare, progressive degeneration of the retina that eventually causes blindness.
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 is exhibited mainly in males who inherit one abnormal gene from their mother. In some people, mostly males, an inherited form of hearing loss may be associated (Usher's syndrome).
The photoreceptors 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 a small area of central vision and possibly some peripheral vision remaining (tunnel vision).
When examining the retina with an ophthalmoscope, a doctor sees specific changes that suggest the diagnosis. Several tests, such as the electroretinogram, which is a test of the electrical response of the retina to light, may help make the diagnosis. No conventional treatment can slow the progression of retinal damage. High doses of vitamin A are recommended by some doctors, but the value of this treatment is unknown. However, an experimental treatment in which fetal retinal tissue is transplanted into people with retinitis pigmentosa has been reported to improve vision.
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