What is it?
Retinitis pigmentosa (RP) is the name given to a group of inherited disorders that affect the light-sensitive part of the eye (the retina). It is the most common inherited eye condition, affecting 1 in 4,000. RP is a result of a decline in the cells that detect light (photoreceptor cells) which ultimately leads to sight loss, and some will lead to blindness.
RP linked conditions
Usually, the inherited faulty genes only affect the eyes, however in some cases they can affect other body parts. One example is Usher syndrome, in which there is hearing loss which is present from birth but the later development of RP. RP is also a feature of several other genetic syndromes, including Bardet-Biedl syndrome, Refsum disease, and NARP (neuropathy, ataxia, and retinitis pigmentosa).
RP is caused by faults in any of around 200 genes (that we know of so far). These can be passed on through families in different patterns, depending on the type of RP. For example some people develop the condition if they inherit a particular genetic fault from both parents, who are themselves healthy. In other cases a parent or other older relative may also be affected. About half of patients have no family history of RP.
SymptomsSight loss from RP happens gradually, over many years. The first cells to die are the photoreceptor cells known as ‘rods’. They are the cells we use in dim light, so night blindness is an early symptom. Later RP can affect the photoreceptors known as ‘cones’. These are used for seeing in colour and function at higher light levels. Cones in the peripheral retina are important for peripheral vision and the cones in the central retina are responsible for detailed vision used for example in reading and recognising faces. Usually the peripheral cones are affected before central cones so patients will first notice peripheral field loss in addition to night blindness.
Symptoms tend to appear between childhood and the age of 30 but some uncommon forms of RP do not give rise to symptoms until much later. The speed at which sight gets worse varies with the different genetic forms of RP.
There is currently no cure for RP. However people with RP may develop cataracts at an earlier age than normal. If so, cataract surgery may help improve vision. Another complication of RP is waterlogging of the central retina (macular oedema) and this can be treated with medications such as steroid eye drops, and acetazolamide given as drops of by mouth.
Research using new genetic technologies has led to the discovery of many genes causing RP. Fight for Sight researchers have been at the forefront of this research effort.
Finding the genes means that people can be given a better idea of how the condition will affect themselves and their families in future. However there are still many people with RP who do not know which gene is causing their condition and there are still RP genes to be discovered.
Finding the RP genes is the first step in the path to develop effective treatments. Research is taking several different approaches to restoring sight or preventing RP from progressing.
Our work with the National Institute for Health Research Horizon Scanning Centre (NIHR HSC) investigated current research to develop new treatments for RP. We identified promising potential treatments, including gene therapy, stem cell therapy, drugs to slow photoreceptor cell death, drugs that protect nerve cells and an artificial retina.
Planning a gene therapy clinical trial for X-linked retinitis pigmentosa1 October 15 - 1 September 18
At the leading edge of gene replacement therapy for inherited eye disorders.Find out more
The RP Genome Project1 September 14 - 31 August 18
Top genetics research institutes working together.Find out more
More retinitis pigmentosa research projects
Siblings Debbie and Adrian White were diagnosed with a rare genetic disorder, called Usher syndrome II. The condition causes hearing impairment and progressive vision loss due to retinitis pigmentosa.
At the age of five it was suggested that Debbie went for a hearing test and when her younger brother, Adrian, was born he was automatically tested. In his case he was born partially deaf.
It was when they hit their teens Adrian visited an opticians, aged 17, he was referred to a consultant at Birmingham Genetic Clinic and was diagnosed with retinitis pigmentosa.
Adrian said: “I can still remember the day I was told that I had this eye disease and I thought what am I going to do? Not only do I have problems with my ears - I’ve now got problems with my eyes.”
At the same time, Debbie, aged 21, was also diagnosed with the condition. Debbie said: “As a big sister you always feel protective over a younger sibling – Adrian’s condition has always been worse than mine. I would willingly swap places with him, as he has always been a very independent person and it would mean the world to us if Fight for Sight could find a cure.”
The condition causes tunnel vision and night blindness and before Debbie’s sight become progressively worse, she was a keen golfer. Debbie said: “When you start losing your sight, you start losing your independence, especially as I can’t drive and I can’t really go out at night on my own without assistance. Giving up playing golf was incredibly difficult too.”
For the past two decades Debbie has been a supporter of Fight for Sight and now chairs the Fight for Sight’s Warwickshire Committee. She decided to share her passion of golf and organises an annual golf day to help raise vital funds for Fight for Sight and eye research.
Debbie also has cataracts forming and has astigmatism of the eye said: “It’s incredible people just disregard my disability because it appears that I look normal. I want to raise awareness so more people understand the condition.”
You could play an important part in eye research by being a participant in clinical research study that may benefit many people. You could even help shape clinical research by becoming more actively involved and having a say. Patients, carer, or anyone with an interest can help.
What are clinical trials
Clinical trials are research studies that find out if a medical strategy, treatment, or device is safe and effective for humans. They are a key research tool for improving medical knowledge and patient care. The people who carry out research are mostly the same doctors and healthcare professionals who treat people. Their aim is to find better ways of treating patients and keeping people healthy.
Here are some ways to find out about research projects and clinical trials that you can get involved in.
UK Clinical Trials Gateway
The UK Clinical Trials Gateway run by the National Institute for Health Research (NIHR) provides easy to understand information about clinical research trials running in the UK, and gives to a large range of information about these trials. It is designed to enable patients and clinicians to locate and contact trials of interest. Visit their website and select the eye condition that you are interested in.
NIHR Clinical Research Network Portfolio
The NIHR Clinical Research Network Portfolio is a database of high-quality clinical research studies in England, Northern Ireland, Scotland and Wales. Within this the Ophthalmology Specialty Group supports a national portfolio of research studies in ophthalmology and the vision sciences. See their website for details.
If you wish to join a trial it is always best to discuss this with your doctor or clinical team first.
Last updated November 2017
Approved by Professor Tony Moore, UCSF School of Medicine