Retinitis pigmentosa is a hereditary progressive retinal degenerations or dystrophies. There is an overlap or variation in various forms of retinitis pigmentosa. The progressive degeneration of the retina which takes place in the day light is known as the rods and cones.
The rods of the retina get affected during the course of the disease and the cones start deteriorating. During the degeneration of the retina, the vision gradually slows down but the central vision remains till the later stage in the disease.
Retinitis pigmentosa is a condition that is inherited in which both the eyes may get affected. If this affects one eye, the other eye also gets affected after a couple of years. There are many ways by which retinitis pigmentosa is caused which includes, recessive, dominant and sex-related recessive ways. In a few cases, a family history also causes this disease.
Retinitis pigmentosa can also be present at birth but it is diagnosed during teen years. The congenital type is nonprogressive and stable. Those cases that are diagnosed late in life progress at a very slow pace. Today, there are about 75,000 people in the U.S suffering from retinitis pigmentosa. This disease is sometimes related with other types of systemic illnesses. One such disease is usher syndrome which is characterized by neural hearing loss and retinitis pigmentosa.
Retinitis pigmentosa results in degeneration of rod, therefore the patient suffering from this disease finds it difficult to see in the night as well as difficulty seeing in the periphery. Gradually, there is a constriction in the vision field which results in tunnel vision. The central vision gets affected in both eyes and this lasts for years.
In most cases, there is total blindness. A person may get affected with legal blindness from childhood to the age of 40.
The retinitis pigmentosa is diagnosed by a general examination. The patient complains that he finds it difficult to see in the night or in dim light, that when he needs to go for a thorough examination. There are two tests that are important in diagnosing this disease:-
Electrophysiological testing is done by the ophthalmologist. Using electrodes by flashes of light are kept on the surface of the eye. The ERG with visual field exam is used for diagnosing.
Visual field testing checks the defects in the peripheral if there is any loss that is related after the disease has occurred. After some time the visual field reduces causing a “tunnel vision” and this later result in a complete loss of vision.
There is no specific cure for retinitis pigmentosa. Many patients have been recommended to go for vitamin A therapy. Other than this, omega-3-rich diet that contains docosahexaenoic acid can make a little difference. This diet includes two 3 ounces of salmon, tuna, mackerel and herring fish.