Retinitis pigmentosa (RP) is a part of a group of inherited eye disorders that affect the retina. The retina is a thin layer of tissue containing millions of light-sensitive nerves that lines the back of the eye. Light rays focus onto the retina, where they are transmitted to the brain and then become the images that you see. In RP, the retinal cells gradually stop working and eventually die. In most cases, the condition first affects the peripheral rod cells, which allow you to see at night, and later affects the central cone cells, responsible for fine detail and color vision.
RP causes permanent vision loss, which usually happens very slowly, over the course of years. Some people with RP become blind, but most people with the condition retain some level of useful vision. If you have RP, there is a 50 to 60 percent chance that someone in your family also has the condition.
In general, a person's rod cells are first affected by RP. Rod cells help with peripheral (side) vision and seeing in dim light or dark places. The first symptom is often "night blindness," which is difficulty seeing in dim light, such as in a darkened room or outdoors at dusk. Healthy eyes naturally adapt to dark light, but eyes affected with RP take much longer to do this or don’t do it all. Some people are also bothered by the glare from sunlight or bright lights.
A series of tests are available to confirm a diagnosis of RP. These include:
Dilated Eye Exam
During a dilated eye exam, you are given special eye drops to dilate your pupils, allowing your ophthalmologist to clearly see the retina at the back of your eye. The drops make you temporarily sensitive to light and cause your vision to be blurry.
A special camera may be used to take photographs of your retina, which help to track the progression of your RP. This may include pictures of the retinal thickness with a camera called an OCT (optical coherence tomography) that uses dim red light.
At this time, there is no cure or treatment available to slow vision loss in RP or associated retinal disorders. However, RP sometimes causes other eye problems that can be treated, such as cataracts or swelling in the retina. Research is being conducted at UCSF and around the world with the aim of developing effective treatments for the disease. Gene therapy, stem cell therapy and growth factors are being scientifically tested as potential treatments for RP.
In addition, a large clinical trial completed in the U.S. in 1993 showed that vitamin A has a small positive effect on visual function, and that vitamin E has a negative effect. The Foundation Fighting Blindness and the National Eye Institute recommended that some adults with RP should take a daily 15,000 international units of vitamin A palmitate supplement and avoid high dose vitamin E to help prolong their vision. Your ophthalmologist will discuss vitamin therapy with you.
Reviewed by health care specialists at UCSF Medical Center.