Understanding Retinitis Pigmentosa
Retinitis pigmentosa (RP) is a rare eye disease which causes damage to the retina, resulting in a loss of vision.
About Retinitis Pigmentosa
The retina is the layer of tissue at the back of the inside of the eye. The cells in the retina convert light into signals to nerve cells, which send signals to the brain; the brain then tells us what we see. The disease is named for the dark deposits that appear in the retina.
RP can be caused by a genetic defect, and can run in families. Early symptoms of the disease are often first experienced in childhood. These symptoms include loss of the ability to see at night or in very low light. Later the disease may lead to blurring of vision, tunnel vision, loss of central vision or loss of the ability to see colors.
In many cases, these severe vision problems do not occur until early adulthood. In advanced stages of the disease, RP can lead to a person being able to see only very bright flashes of light. In some cases, the person may experience total blindness. Other forms of RP and related diseases include Usher syndrome, Leber’s congenital amaurosis, rod-cone disease, and Bardet-Biedl syndrome, among others.
How RP affects vision
Light enters the eye via the cornea. The amount of light that enters is controlled by the iris, which expands or contracts the pupil in response to the brightness of the scene. The lens then focuses the light into a patterned image on the retina. The photoreceptor cells in the retina called “rods” and “cones” convert the light into electrical impulses, which are sent to the brain via the optic nerve. The brain then interprets these impulses and creates what we see. People with RP experience a breakdown and loss of cells in the retina, which affects how well light can be converted into the electrical impulses that are sent to the brain for interpretation.