Retinitis pigmentosa (RP) is a group of diseases characterized by a gradual loss of vision (night and peripheral, predominantly) caused by changes in the retina (pigment and neural cells, blood vessels, etc) [See figure 1].
RP is usually caused by an inherited genetic abnormality. The inheritance pattern can be dominant (passed from one generation to the next), recessive (an abnormal gene from 2 normal vision parents), or X-linked (unaffected mother pass abnormal gene to affected son). New mutations also cause RP.
Vision loss (worse in the dark) and decreased peripheral vision are the most common early symptoms and range from mild to severe, depending upon the stage and course of the disease. The Eye M.D. may detect abnormalities inside the eye; most commonly pigment clumping in the retina, change in the blood vessels and/or paleness of the optic nerve. Cataracts and inflammation occur less frequently. Vision function is typically better in well lit environments. Progressive loss of peripheral vision may eventually limit/eliminate vision.
The Eye MD may perform an electroretinogram (ERG) in the office, lab or operating room outfitted with special equipment. Electrodes are placed on the skin and cornea to measure the electrical response of the retinal cells to a flash of light A visual field test may also be performed to assess the peripheral (side) vision. Dark adaptation and molecular analysis (blood sample) for genetic abnormalities are less frequently administered tests.
RP is usually an isolated finding. However, RP can be associated with other systemic abnormalities including hearing loss (Usher Syndrome).
The age on onset and progression of RP is extremely variable. Some affected people maintain good vision into the 5th or 6th decade, while others have profound vision loss early in life. It is important to have serial exams with the Eye MD to maximize vision and provide resources for help and support.
Although there is no cure, serial examinations and treatment (by an Eye MD) of refractive error, cataracts, swelling of the retina helps maintain the best possible vision. Vitamin supplementation may slow vision loss, but this treatment is controversial and requires direct physician supervision. There are many investigations to help people with RP and in the future gene therapy and/or stem cell therapy may provide significant benefit. Parents and physicians typically communicate with teachers and vision personnel (including low vision specialists) to maximize the education experience.
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