Retinitis Pigmentosa: Symptoms, Genetics and Treatment Options

Retinitis pigmentosa (RP) is not a single disease but a family of inherited conditions in which the light-sensitive cells of the retina slowly stop working and die. It usually begins with difficulty seeing in the dark and a gradual loss of side vision, while sharp central vision is often preserved until much later. Many people describe living with RP as looking at the world through a slowly narrowing tube.

RP is one of the most common inherited retinal dystrophies, affecting roughly one in 3,000 to 4,000 people worldwide. For a long time, doctors could offer little beyond a diagnosis. That is changing: genetic testing now identifies the cause in a large proportion of families, the first approved gene therapy has shown that treatment is possible for one specific form, and many clinical trials are under way. Equally important, practical low vision support can make a big difference to independence today.

What happens in the retina?

The retina is the thin layer of nerve tissue lining the back of the eye. It contains two main kinds of photoreceptor: rods, which work in dim light and dominate the peripheral retina, and cones, which provide colour and sharp detail and are concentrated in the macula at the centre. Our guide to how vision works explains this in more detail.

In most forms of RP, a genetic fault first affects the rods, so night vision and side vision decline. Over years, the cones are affected too, eventually reducing central vision and colour perception. As cells are lost, clumps of dark pigment appear in the retina. These deposits, which look like bone spicules to the examining doctor, gave the condition its name, although it is not actually an inflammation as the word retinitis suggests.

RP can occur on its own (non-syndromic RP), or as part of a syndrome affecting other parts of the body. The best known is Usher syndrome, which combines RP with hearing loss and sometimes balance problems. Others include Bardet-Biedl syndrome, which can involve obesity, extra fingers or toes and kidney problems.

Symptoms: night blindness and tunnel vision

The age at which symptoms start and the speed of progression vary enormously, even within the same family. Some people notice problems in childhood, others only in middle age.

• Night blindness (nyctalopia) – difficulty seeing in dim light, walking in the dark or adjusting when moving from a bright room into a dark one. This is often the first symptom. See our guide on night blindness for other causes.
• Loss of peripheral vision – bumping into furniture or door frames, tripping over objects at ground level, or not noticing people approaching from the side. Because central vision is preserved, many people adapt unconsciously and only realise how much field they have lost when tested.
• Glare sensitivity – bright light and sunlight can be uncomfortable and slow to recover from.
• Reduced contrast and colour vision – later in the disease.
• Flickering or shimmering lights (photopsias) – reported by some people.
• Loss of central vision – usually late, though macular swelling or cataract can blur central vision earlier.

How retinitis pigmentosa is inherited

RP is caused by changes (variants or mutations) in genes needed for the health of photoreceptors or the retinal pigment epithelium, the supporting layer beneath them. More than 80 genes are known to cause non-syndromic RP, and the pattern of inheritance affects the risk for relatives. Our article on family history and eye disease risk gives broader background.

• Autosomal dominant – one altered copy of the gene is enough. An affected parent has a 50 percent chance of passing it to each child. This form often progresses more slowly. The RHO (rhodopsin) gene is a common cause.
• Autosomal recessive – both copies must be altered. Parents are usually unaffected carriers, and each child has a 25 percent chance of being affected. Many genes fall into this group, including USH2A and RPE65.
• X-linked – the gene is on the X chromosome. Males are mainly affected and often have earlier, more severe disease; carrier females can have mild or sometimes significant symptoms. RPGR is the most common gene.
• Simplex cases – many people have no known family history. The condition may still be inherited, often recessively, which is one reason genetic testing is so valuable.

Diagnosis and genetic testing

An eye specialist, ideally one with experience in inherited retinal disease, will usually perform:

• A full eye examination, including a dilated view of the retina showing pigment deposits, narrowed blood vessels and a pale optic disc.
• Visual field testing to map remaining side vision, often showing a ring-shaped or concentric loss.
• Electroretinography (ERG), which measures the electrical response of rods and cones to light and is often reduced or absent even early in the disease.
• Optical coherence tomography (OCT) to look at the layers of the retina and detect macular swelling.
• Fundus autofluorescence imaging, which shows patterns of stressed and lost retinal cells.

Why genetic testing matters

Genetic testing, usually a blood or saliva sample analysed with a panel of retinal genes, can identify the cause in a majority of patients with RP, though not all. It is best done together with genetic counselling. Benefits include:

• Confirming the diagnosis and distinguishing RP from conditions that look similar, some of which are treatable (for example vitamin A deficiency, certain drug toxicities or inflammatory diseases).
• Clarifying the inheritance pattern and the risk for children, siblings and other relatives.
• Pointing to possible syndromes, so that hearing, kidney or other checks can be arranged.
• Establishing eligibility for approved gene therapy or for clinical trials, which almost always require a confirmed genetic diagnosis.
• Providing information for family planning options, which a genetic counsellor can discuss sensitively.

Gene therapy: voretigene neparvovec for RPE65

In 2017 the US Food and Drug Administration approved voretigene neparvovec (brand name Luxturna), and it was later approved in Europe and other regions. It was the first gene therapy approved for an inherited disease of any kind in the United States.

It is designed for people with confirmed mutations in both copies of the RPE65 gene who still have enough viable retinal cells. RPE65 provides an enzyme needed to recycle vitamin A in the visual cycle; without it, photoreceptors cannot respond to light properly. Voretigene uses a harmless modified virus (an adeno-associated virus, or AAV) to deliver a working copy of the gene. A surgeon injects it under the retina during a vitrectomy operation, one eye at a time.

In clinical trials, treated patients showed meaningful improvements in their ability to find their way through a mobility course in dim light and in light sensitivity. It is important to have realistic expectations:

• RPE65 mutations account for only a small proportion of RP and related conditions, so most people with RP are not eligible.
• The treatment improves function in surviving cells; it cannot replace cells that have already died, so earlier treatment is generally better.
• Long-term follow-up is still ongoing, and some studies have reported continued retinal thinning or atrophy in treated areas.
• It is a specialised surgery with risks, offered only in designated centres.

Other research directions

Many approaches are being studied, including gene therapies for other genes (such as RPGR for X-linked RP), gene editing, RNA-based therapies, optogenetics (making surviving retinal cells light-sensitive), cell transplantation and treatments aimed at slowing cell death regardless of the gene. Retinal implants (bionic eyes) have been used for people with very advanced disease, offering limited light and shape perception. Be cautious about clinics offering unproven stem cell injections for a fee outside regulated trials; serious complications, including blindness, have been reported.

Treatable complications

• Cataract – people with RP often develop a posterior subcapsular cataract at a younger age. Removing it can noticeably improve vision; see our cataract guide.
• Cystoid macular oedema – fluid in the central retina that blurs vision. It may respond to certain eye drops or tablets prescribed by a specialist.
• Epiretinal membrane – a thin film on the retina surface that can distort vision and sometimes needs surgery.

Vitamins, diet and lifestyle

Some older studies suggested that high-dose vitamin A palmitate might slightly slow the decline of the retinal response in certain adults with RP, but the effect was small and the topic remains debated. High-dose vitamin A can cause liver damage and is harmful in pregnancy, and it may be harmful in some genetic types, such as ABCA4-related disease. Never start high-dose supplements without guidance from a retinal specialist. A healthy, varied diet, as described in our nutrition guide, is sensible for everyone.

Wearing good-quality sunglasses with UV protection outdoors improves comfort and reduces glare; many people with RP find amber or orange filter tints especially helpful. Not smoking supports overall eye and vascular health. Eye exercises do not slow or reverse RP, and claims that they restore lost vision are not supported by evidence.

Living with RP: low vision support

Low vision rehabilitation focuses on using remaining vision as effectively as possible and finding alternatives where vision is not enough. Our low vision guide covers these services in depth. Typical support includes:

• Orientation and mobility training – learning safe techniques for walking, crossing roads and using public transport, including use of a long cane when appropriate.
• Lighting – bright, even lighting at home, lights on stairs and in hallways, motion-sensor night lights and a powerful torch for evenings.
• Contrast – coloured tape on step edges, contrasting crockery and furniture, and decluttered walkways.
• Technology – screen magnifiers, high-contrast settings, voice assistants, screen readers and smartphone apps that read text aloud or describe surroundings.
• Field-awareness strategies – training in scanning techniques to make the most of a narrow field.
• Driving – many people with RP eventually do not meet the visual field standard for driving. Your doctor can advise on the rules where you live; driving at night is usually the first thing to give up.
• Education and work – children may need classroom adaptations, and adults may be entitled to workplace adjustments.
• Emotional wellbeing – a progressive condition can bring grief and anxiety. Peer support groups and counselling help many people.

When to see a doctor: warning signs

Regular follow-up, typically once a year or as advised, helps track changes, catch treatable complications and keep you informed about new trials.