What Is Retinitis Pigmentosa?

Retinitis pigmentosa (RP) is the name given to a group of diseases of the retina, collectively called inherited retinal dystrophies, that all lead to a gradual progressive reduction in vision.

Two million people worldwide suffer from inherited retinal diseases (IRDs), of which retinitis pigmentosa is the most common. Collectively, they are the major cause of inherited sight loss, ultimately often leading to total blindness and with profound impacts on patients, their families and society.

There is currently no treatment or cure for RP. Research is being carried out to find the genetic causes with the hope of finding new potential treatments.

Causes of retinitis pigmentosa

Almost all types of retinitis pigmentosa are inherited, caused by genetic mutation. These faulty genes lead to retinal cells not functioning properly and dying, so the eye is unable to process light that hits these retinal cells, causing gradual vision loss.

There are many genes that cause retinal cells to stop working, so there are many different types of RP.

It affects approximately 1 in 3,000 to 4,000 people. In roughly half of all cases, there are other family members with RP. There are three main ways in which RP can be passed from parent(s) to child:

• Autosomal recessive inheritance - Caused as a result of two copies of the mutated gene being present when both parents are carriers. The result may be that the child will either become a carrier or develop the disorder. However, it can also not affect the child at all.
• Autosomal dominant inheritance - Caused because of one parent having a dominant gene mutation, meaning a 1 in 2 chance that the child will inherit and subsequently develop retinitis pigmentosa.
• X-linked inheritance - If the mother is the parent with RP linked to their X chromosome, there is a 50% chance of their son developing RP and the same odds of their daughter being a carrier.

Symptoms of retinitis pigmentosa

The age at which symptoms start and the rate of deterioration are variable - for example, with the different genetic types - but generally very slow, with changes occurring over years rather than months.

Difficulties with night vision and peripheral vision are the first things that are noticed. Later, reading vision (detailed vision), colour vision, and central ('straight-ahead') vision are affected.

If you notice any of these symptoms, it is important to have your eyes tested by an optometrist.

Diagnosing retinitis pigmentosa

During a standard eye test, your optometrist will examine your retina to detect RP.

If you know that a family member has RP, it is important to tell your optometrist, as this could help them to diagnose the condition.

If your optometrist detects any changes to your retina, you will be referred to an ophthalmologist at your local eye hospital for further tests.

Treatment for retinitis pigmentosa

There is currently no treatment or cure for RP. Once diagnosed, you will be monitored regularly at your local eye hospital and given advice on how to make the most of the vision you do have.

Find out how Assistive Technology helps to manage tasks made difficult by low vision and blindness.