Retinitis pigmentosa (RP) is a group of diseases that begin to affect sight in adolescence or early adulthood, resulting in eventual legal blindness. The cells within the retina that send visual images to the brain start to die.
The retina, which is attached to the back of the eye, is connected to the brain and has different types of cells that relay information to the brain. The type of vision loss depends upon the cells that are affected.
Fortunately for some patients, there are several new therapies that are showing some success in slowing or reversing the effects of retinitis pigmentosa.
What are the symptoms of RP?
Symptoms of RP will depend upon the cells affected. Rod cells are mostly concentrated in the outer layer of the retina and are responsible for the transmission of dim light imagery. When these cells begin to die, night and peripheral (side) vision are affected.
Cone cells are located near the center of the retina and transmit color and central vision.
How is RP contracted?
RP is the result of genetic mutations passed down from parents to children. Parents may carry the genes and not be affected, but their children may develop RP. Gender may also play a role, with sons of a mother with a genetic mutation developing RP while their daughters remain unaffected.
What treatments are available for RP?
Microchip retinal implants
Clinical trials for retinal implants have been achieving success in enabling RP patients to restore some of their visual acuity. The newest implants have power sources embedded under the skin. They can also be removed and re-implanted as the technology develops.
While implants initially provide only outlines and different shades of gray in some individuals, researchers are finding that their brains are adapting to the images provided by the implants and are interpreting and refining them into familiar images. Some individuals can recognize faces, read bold type and street signs, and exhibit other life enhancing improvements.
Gene therapy is being used in several clinical trials and is achieving various degrees of success. Genetic mutations are being manipulated by the introduction of an Adeno-Associated Virus (AAV), which is a mild virus that overwhelms mutated genes with good substitutes or replaces retinal proteins that are necessary for proper function.
A diet that is rich is omega-3 DHA, vitamin A, and Lutein, which is found in eggs and leafy green vegetables, has been found to reduce the pace of vision loss in RP patients.
While many clinical trials and treatments for RP have only been available outside of the United States, the Food and Drug Administration has recently approved the use of retinal implants for RP patients in the United States.