Retinitis pigmentosa (RP)

What happens in this disease?

The retina is a thin layer at the back of the eye that senses light. It contains light cells called rods and cones. In RP, these cells slowly break down. First the rods, which allow vision in the dark, are affected, then the cones. Sometimes RP is part of a syndrome together with other problems such as hearing loss.

Which symptoms can occur?

Symptoms usually begin in childhood or young adulthood. How fast vision is lost varies from person to person.

• Difficulty seeing at night and in dim light (first symptom)
• Loss of side vision, over time tunnel vision
• Discomfort from bright light
• Reduced color vision
• In later stages, central vision also gets worse; reading and recognizing faces become difficult
• Additional eye problems such as cataract or fluid build-up in the retina

How is it diagnosed?

The eye doctor widens the pupil with drops and looks at the retina. A visual field test measures side vision. A test called ERG measures how the retina responds to light. OCT takes a detailed picture of the retina. A genetic test helps to find out the type of RP.

Treatment and care

There is not yet a treatment that stops most types of RP. For people with low vision, aids and vision training help them make the best use of their remaining sight. Some vitamin supplements may slow the loss. But too much can be harmful, so it is necessary to ask the doctor. Regular eye checks catch additional problems such as cataract early. Sunglasses protect the eyes from light. There is an approved gene therapy for a small group with two changes in the RPE65 gene. Research on gene, cell and drug therapies is ongoing. The doctor who follows the disease decides which treatment is suitable.

For the family: inheritance and genetic counselling

RP can be inherited in different ways. In the dominant type, the chance of passing it from an affected parent to a child is 1 in 2 in each pregnancy. In the recessive type, the chance of an affected child for a carrier couple in each pregnancy is 1 in 4. Recessive types may be more likely when parents are related by blood. In the X-linked type, mostly males are affected. Genetic counselling explains the type and the risk in the family.