Retinitis pigmentosa (RP) is an eye disease that is inherited, and relatively rare. About one in four thousand Americans are affected by this disease. The retina, which is the light-sensitive portion of the eye, degenerates progressively over time. The result of this degeneration is the loss of peripheral vision, loss of central vision, night blindness, and sometimes blindness.
Retinitis Pigmentosa Symptoms
Childhood is usually when the first symptoms of retinitis pigmentosa appear. Typically both eyes are affected by the disease. Sometimes RP doesn’t appear until older age, at age 30 or even older.
The main symptom of RP in the beginning stages is night blindness. Tunnel vision develops in the later stages of the disease, and eventually central vision is affected.
Causes of Retinitis Pigmentosa
Very little is known about the causes of RP, beyond that it is an inherited disease. Scientists believe that defective molecules in our genes cause RP. If one parent carries the defective gene, it’s possible to get RP, even if your parents do not have the disease.
RP affects the retina in the eye. The disease causes the light-sensitive cells that are located in the retina to die gradually. Most often, the cells that are used for night and peripheral vision, called rod cells, are affected. Sometimes the cells that are used to see color and for central vision, called cones, are also affected.
Diagnosis and Treatment
The main diagnostic tool employed is visual field testing. This test determines how much peripheral vision loss has occurred. Other diagnostic tools may be used to test night vision and color vision. There is also classic pigment clumping in the retina that can be seen with a dilated eye exam.
Few treatments exist for RP. What is available helps conditions associated with RP, not the disease itself. For patients older than 25, there is a prosthesis system that was recently approved. This system captures images via glasses, and transmits the signal captures to an implanted device located on the retina. Not every person is a good candidate for this and the procedure has significant limitations.
Most treatments center around helping the patient learn to deal with their vision loss. A Low Vision Evaluation by a licensed Doctor of Optometry who specializes in Low Vision will help to optimize visual function. Psychological counseling, training by a Mobility Specialist and Occupational Therapy, may be recommended. Some doctors recommend vitamin A Palmitate supplements, as there is some evidence that vitamin A might help delay the progression of the disease.