The eye is a globe with three separate outer layers. The outer layer is the sclera, or the white of the eye. The second layer is the choroid. It’s made up of a delicate network of blood vessels and connective tissue. The inner layer is the retina, which has two special kinds of cells that send images to the brain. These light-sensitive cells are rods and cones. Retinitis pigmentosa is a group of diseases affecting the retina. Retinitis pigmentosa destroys rods in the retina, which causes a slow loss of vision and can ultimately result in blindness. About 1 in 4000 people have this disorder.
The cause is unknown. A mutation in the gene that controls rod cells may lead to the disorder. Sometimes, cone cells are also damaged. This disorder is inherited and usually passed from parents to children. It’s not contagious.
Progressive night blindness and the loss of side (peripheral) vision occur. These usually start during the teen years or young adulthood. As side vision worsens, people are left with tunnel vision. They may often have accidents such as tripping and falling. As side vision continues to get worse, many times people can see only what is directly in front. The presence of dark deposits in the retina is the main sign of the disorder.
The health care provider makes a diagnosis from the medical history and physical examination. An examination of the back of the eye with an ophthalmoscope shows pigmented (dark) spots on the retina. An ophthalmoscope is a small scope, with a light at the end, that’s used to see the retina.
There is no proven effective therapy for retinitis pigmentosa. In some rare forms of the disorder, vitamin E and vitamin A supplements have some benefit. Aids including magnifying glasses and infrared night vision scopes can help people with night blindness and tunnel vision. Wearing sunglasses can protect the retina from ultraviolet light and may help preserve some vision.
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Copyright © 2016 by Saunders, an imprint of Elsevier, Inc.
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