Retinitis pigmentosa – RNIB – RNIB – supporting blind and …

About retinitis pigmentosa

Retinitis pigmentosa (RP) is the name given to a diverse group of inherited eye disorders. These eye conditions affect a part of your eye called the retina. RP causes permanent changes to your vision but how quickly this happens and how it changes differs between people. These changes may include difficulty with vision in dim light or the dark and the loss of your side or peripheral vision.

If you have RP, sight loss is gradual but progresses over a period of many years. Some people with RP might become blind but most people with RP keep some useful vision well into old age.

New research is constantly changing our understanding of RP. The British Retinitis Pigmentosa Society (RP Fighting Blindness) website and leaflets offer current updates with detailed explanations of these issues.

When you look at something, light passes through the front of your eye, and is focused by the lens onto your retina. The retina is a delicate tissue that is sensitive to light. It converts the light into electrical signals that travel along the optic nerve to your brain. The brain then interprets these signals to "see" the world around you.

The retina has two main layers, a thin one called the pigment epithelium and a thicker one, called the neural retina. The neural retina contains many millions of cells called photoreceptors and these cells convert light into electrical signals that travel to the brain.

Light is focused onto a tiny area of the central retina called the macula. This specialised area of the retina is about the size of a pinhead. The macula contains a few million specialised photoreceptors called cone cells. These cone cells work best in bright light levels and allow you to see fine detail for activities such as reading and writing and to recognise colours.

The rest of the retina, called the peripheral retina, is mostly made up of the other type of photoreceptor called rod cells. Rod cells enable us to see when light is dim and provide peripheral vision. Peripheral vision is what you can see to the sides and above and below when you are looking at something straight ahead.

All types of RP affect the retina. The retinal cells gradually stop working and eventually die. In most cases, the peripheral rod cells are affected first and RP later affects the central cone cells. The symptoms you experience depend on the way your retina is affected by RP and can be very different from person to person.

Almost all types of RP are inherited, caused by a fault in the genetic information passed down from a parent. The genes we inherit contain the instructions that tell our body how to grow, repair and renew. When a gene is faulty these instructions are faulty and the cells using those instructions do not work as they should. In RP, the faulty genes cause the retinal cells to stop working and eventually die off. Researchers have found many of the genes which, when faulty, cause RP but there is still work to be done to discover them all.

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Retinitis pigmentosa - RNIB - RNIB - supporting blind and ...