Retinitis pigmentosa is an eye disease in which there is damage to the retina. The damage gets worse (progresses) over time. People with this condition have problems with night vision and peripheral vision.

Retinitis pigmentosa commonly runs in families. The disorder can be caused by a number of genetic defects.

The cells controlling night vision (rods) are most likely to be affected. However, in some cases, retinal cone cells are damaged the most. The main sign of the disease is the presence of dark pigmented spots in the retina.

As the disease gets worse, peripheral vision is gradually lost. The condition may eventually lead to blindness, but usually not complete blindness. Signs and symptoms often first appear in childhood, but severe visual problems do not usually develop until early adulthood.

The main risk factor is a family history of retinitis pigmentosa. It is an uncommon condition affecting about 1 in 4,000 people in the United States.

• Vision decreased at night or in reduced light
• Loss of peripheral vision
• Loss of central vision (in advanced cases)

Tests determine the integrity of the retina:

• Visual acuity
• Refraction test
• Color defectiveness determination
• Pupillary reflex response
• Slit lamp examination
• Intraocular pressure determination
• Retinal examination by ophthalmoscopy
• Ultrasound of the eye
• Retinal photography
• Fluorescein angiography
• Electroretinogram (a record of the action currents of the retina produced by visual stimuli)

There is no effective treatment for this condition. The use of sunglasses to protect the retina from ultraviolet light may help preserve vision.

Controversial studies have suggested that treatment with antioxidant agents (such as vitamin A palmitate) may delay the disease from getting worse.

Referral to a low vision specialist is very helpful. Patients should make regular visits to an eye care specialist to screen for the development of cataracts or retinal swelling -- both of which can be treated.

The disorder will continue to progress, although slowly. Complete blindness is uncommon.

Peripheral and central loss of vision will eventually occur.

Many other syndromes with features similar to retinitis pigmentosa have been described, including:

• Friedreich's ataxia
• Mucopolysaccharidosis
• Muscular dystrophy (myotonic dystrophy)
• Laurence-Moon syndrome (also called Laurence-Moon-Bardet-Biedl syndrome)
• Usher's syndrome

Call your health care provider if night vision becomes difficult or if other symptoms of this disorder develop.

Genetic counseling may determine the risk of this disease occurring in a person's children.