Retinitis pigmentosa (RP) is a group of inherited eye diseases that often leads to severe visual problems. The retina is a layer of light-sensitive tissue that lines the back of the eye. It converts visual images that we see into nerve impulses that it sends to the brain. Some types of RP are associated with other inherited conditions. This disorder is named for the irregular clumps of black pigment that usually occur in the retina with this disease.
Many types of RP are caused by a genetic mutation. Some cases occur sporadically. Vision loss occurs when light-sensitive cells in the retina gradually break down. There are two types of cells in the retina:
In most forms of retinitis pigmentosa, the rods die. Vision, thus, becomes impaired at night. The ability to see things off to the side while looking ahead also decreases. In some forms of RP, the cones are lost. In those cases, central and color vision suffers. Vision loss usually progresses over a period of many years.
A risk factor is something that increases your chance of getting a disease or condition.
Risk factors for RP include:
Loss of vision is usually first noted in childhood or early adulthood. The disease gradually worsens. After a number of years, vision loss may become severe. Symptoms vary, depending on the type of retinal cell that is affected. Both eyes often experience similar vision loss. It should be noted that RP is a slowly progressive disease over many years and that most patients never become completely blind. In fact, even though many people with RP are considered “legally blind,” it is only because they have very constricted fields of vision (poor peripheral vision). Some still maintain excellent central visual acuity. Overall, symptoms may include:
Blurry vision from cataracts may complicate RP later in the disease.
Your doctor will ask about your symptoms and medical history, and perform an eye exam. You may be referred to an eye specialist, such as an ophthalmologist.
Vision tests may include:
There is no effective treatment or cure for retinitis pigmentosa. Treatment aims to help you function with the vision that you have. Your doctor can counsel you about expected patterns of vision loss based on the type of RP you have. Recommendations include:
One study implied that large doses of vitamin A can slow the progression of RP by approximately 2% per year. However, the use of this finding is controversial. For one, it is a very mild effect given the large dose. Secondly, there may be side effects of such large doses of vitamin A. Always talk to your doctor before taking any supplements.
Although no direct link has been established, it is generally recommended that everybody, especially patients with disorders such as RP, wear dark UV-protected sunglasses and a wide-brimmed hat in bright, sunny conditions, such as while skiing or at the beach.
These may include the following:
Some community organizations offer classes to help people with vision loss adjust and learn how to use vision aids. If you are considered legally blind, you are entitled to many low-vision services at no cost.
RESOURCES:
The Foundation Fighting Blindness
http://www.blindness.org
Prevent Blindness America
http://www.preventblindness.org
RP International
http://www.rpinternational.org
CANADIAN RESOURCES:
Canadian Association of Optometrists
http://www.opto.ca/en/public/
The Canadian National Institute for the Blind
http://www.cnib.ca/en/Default.aspx
References:
Cecil Textbook of Medicine . 21st ed. WB Saunders Co; 2000.
The Foundation of the American Academy of Ophthalmology. Retina and Vitreous, Basic and Clinical Science Course . 2001-2002.
Harrison's Principles of Internal Medicine . 14th ed. The McGraw-Hill Companies; 2000.
Ophthalmology . Mosby International Ltd; 1999.
Last reviewed November 2008 by Christopher Cheyer, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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