Retinitis pigmentosa

What is it?

Retinitis pigmentosa (RP) is an eye disease. It leads to gradual loss of vision and, sometimes, blindness.

RP occurs when the light-sensing cells in the eye break down. These cells, called rods and cones, are located in the retina. This is the back portion of the eye that receives light coming into the eye, and sends that visual information to the brain.

The symptoms of RP usually begin in young adulthood, although they can begin in childhood. Most people with RP are legally blind by the age of 40, although they still have some vision. The total amount of vision loss and how quickly the disease worsens vary from person to person.

RP is primarily an inherited disorder. However, in some cases the disease occurs in people who do not have a family history of the disease.

The disorder also can show up as part of other syndromes. These include Bassen-Kornzweig disease or Kearns-Sayre syndrome.

Symptoms

The first symptom of RP is usually diminished night vision. It becomes more difficult to see in dimly lit or dark places.

People with RP also slowly lose peripheral (side) vision and visual sharpness.

Over time, the disorder leads to tunnel vision. The outer edges of vision are dark, leaving a shrinking circle of vision in the center.

Eventually, people with RP can go blind. But most people with this disorder retain some vision, even in old age.

Diagnosis

You will be diagnosed by an ophthalmologist. This is a doctor who specializes in eye disorders.

The ophthalmologist may do a number of diagnostic tests. The physician will use an instrument called an ophthalmoscope to look at the inside of the eye through the pupil. In a normal eye, the physician will see an orange or orange-red area called the fundus. In a person with RP, the orange area will have brown or black blotches.

Visual-field tests can be done to measure a person's peripheral vision.

To confirm a diagnosis of retinitis pigmentosa, an ophthalmologist may do an electroretinogram (ERG). During this test, lights of different colors and intensities are flashed into your eye as you peer into a large reflective globe. A contact lens that contains an electrode is placed on your eye. A wire transmits a record of your eye's retina activity. The ERG creates a paper tracing of electrical impulses. People with RP have lower-than-normal electrical activity in their retina.

Expected duration

Most often, RP is an inherited disorder.

Doctors performing an eye examination can see the first signs of RP as early as age 10. Symptoms typically begin in adolescence or young adulthood. They slowly worsen over time.

The severity of the disease varies from person to person. However, the disorder and visual loss last a lifetime.

Prevention

Because RP is a genetic disorder, there is no way to prevent it. There is no proven way to prevent or delay the associated vision loss.

Treatment

There is no known treatment for RP.

Some research suggests that high doses of vitamin A (15,000 IU/day) may slow degeneration a little in some people. However, the evidence for this is not strong. In addition, there are potential toxic effects of taking too much vitamin A.

If you have RP and want to try vitamin A therapy, talk with your physician first. Ask about the safety and potential value of this treatment.

Some experts recommend increasing the intake of dietary omega-3 fatty acids, but there is no evidence that omega-3 supplements help. Also, it's best for people with early RP to avoid vitamin E supplements.

Some patients with RP develop macular edema. Fluid accumulation in the central part of the eye can accelerate vision loss. This can be treated with a carbonic anhydrase inhibitor in oral form or as eye drops. A commonly used oral drug is acetazolamide.

When to call a professional

See your health care professional if you notice any change in your vision. This includes a decreased ability to see at night or loss of peripheral vision.

Prognosis

RP cannot be cured. The visual loss is both progressive and permanent.

The amount and speed of degeneration varies by individual. Therefore, the extent of vision loss cannot be predicted.

Many patients afflicted with this condition lead fairly normal lives.

Additional info

American Academy of Ophthalmology
https://www.aao.org/

National Eye Institute
https://www.nei.nih.gov/