Retinitis pigmentosa and inherited retinal dystrophies

Different IRDs may affect sight in different ways to one another. Most IRDs cause ongoing (progressive) and permanent changes that reduce your vision. These changes usually happen slowly, taking years to develop.

This page contains a summary of our information on RP and IRDs. To read our full information, download our Understanding Retinitis pigmentosa and inherited retinal dystrophies booklet, which is accredited by the Royal College of Ophthalmologists:

When light enters your eye, it is focused onto your retina at the back of your eye. The retina has layers that must work together to enable you to see. One of these layers contains special cells known as rods and cones. Rods and cones are sensitive to light, and they change light into electrical impulses. These electrical impulses pass along the optic nerve of the eye to reach the brain. Our brain processes these signals to give us vision.

The central part of the retina is called the macula. The macula contains millions of cone cells. Cone cells work best in bright light. They help us recognise colours and see in detail, for example when we read, write, and look at people’s faces. This is known as our central vision.

The peripheral retina is mostly made up of rod cells. Rod cells allow us to see in dim light, such as at night, and they help us detect movement. They also help us to see what’s around us when we’re looking straight ahead to give us our side (peripheral) vision.

The way in which your sight is affected depends on the type of IRD you have. Most forms of IRD affect night vision and peripheral vision first, but there are some which affect central vision first.

IRDs are hereditary conditions caused by a change (fault) in one of the genes involved in maintaining the health of the retina. In an IRD, the changed gene stops your retinal cells from working correctly over time. Genes usually come in pairs. You inherit one gene from each of your parents to make each pair. When you have children, you only pass on one gene to them.

You can inherit IRDs in different inheritance patterns:

Autosomal dominant (AD).

This means that usually one parent has the condition. Each time that parent has a child, there is a 1 in 2 chance of the child having the condition as well.

Autosomal recessive (AR).

This means that neither parent has the condition themselves, but both parents are “carriers”. When both parents are carriers, every time they have a child, there is a 1 in 4 chance that the child will have the condition.

X-linked (XL).

X-linked conditions mainly affect males. Males who inherit the changed gene will be affected by the condition. Females who inherit the changed gene will usually be carriers. When a male has an X-linked IRD:

• each of his daughters will be carriers of the condition. 
• none of his sons will inherit the condition and they will not be carriers.

When a female is a carrier of an X-linked IRD:

• each of her daughters has a 1 in 2 chance of also becoming a carrier.
• each of her sons has a 1 in 2 chance of inheriting the condition.

Retinitis pigmentosa, often called RP, is the name given to the most common group of IRDs. The genes that cause RP affect the rod cells in the retina first so that they gradually stop working over time. The cone cells are affected later on. The age that symptoms start will depend on the genes that have caused your RP. Some people may notice their first symptoms in early childhood. Others may notice these symptoms between adolescence and early adulthood. Some people don’t have symptoms until later in life.

The symptoms of RP include:

• Night blindness – difficulty seeing in dim light, such as outside at dusk or at night.
• Peripheral vision loss – difficulty seeing things that are in your peripheral (side) vision.
• Progressive change in vision over time – this will mean continual readaptation to these vision changes over time.
• Increased light sensitivity – more glare from bright lights and sunlight.
• Delayed adaptation – difficulty when moving between light and dark environments.
• Seeing flashing lights and colours – noticed usually when a person has already lost a lot of their sight. It is important to discuss any new symptoms you have like this with your ophthalmologist (hospital eye doctor) or optometrist (optician) as soon as you notice them.

There are many IRDs that are caused by many genes. Some have similar symptoms to RP, and some are very different. Some IRDs affect the whole retina, and others only affect the macula in the central retina. IRDs can be grouped into different types depending on the retinal cells affected. These include:

Rod-cone dystrophies – where the rod cells are more affected than the cone cells. This causes night blindness and peripheral vision loss. Most rod-cone dystrophies also affect cones in the later stages, affecting central vision later on.

Cone-rod dystrophies – where the cones are affected earlier and more severely than the rods. This means central vision is affected more than side vision in the early stages.

Macular dystrophies – which affect the macula and your central vision. They often leave side vision intact.

Cone dysfunction syndromes – which only affect the cone cells of the retina.

Choroidal dystrophies – which affect how the choroid and the retinal pigment epithelium (RPE) work. The choroid and RPE lie underneath the retina and support the retina so that it can work properly. They affect side vision first with central vision affected later on.

Syndromes which include IRDs – where other aspects of the body and general health are also affected as well as the eyes.

Currently, there is a gene therapy treatment available on the NHS for an IRD known as Leber congenital amaurosis (LCA). This condition is associated with a gene change on gene RPE65. Apart from this, there is still no treatment or cure for IRDs. However, ongoing research is taking place all the time.

The types of treatment currently being investigated include:

• Gene therapy. Normal genetic material is introduced into the affected retina to override the gene change. For this to have any chance of success, there must be some retinal cells that are still working. Gene therapy relies on knowing which specific gene has caused the condition.
• Gene editing. If the affected gene is large, it makes it difficult to be able to replace the whole gene. Instead, scientists “cut out” the changed section of the gene and replace it with a normal section instead. However, this approach needs further development so that it is precise enough to ensure that normal genes are not damaged in the process.
• Optogenetics. This is still being explored as a potential treatment for more advanced conditions where retinal rods and cones are no longer working. Optogenetics aims to make other cells in the retina respond to light, making them act like rods and cones. This is done by introducing genes into the retina that change the cells’ behaviour.
• Stem cell therapy. Stem cells are cells that have not yet specialised to form a specific tissue in the body. If stem cells could be turned into retinal rods and cones, it may be possible to replace the cells that have stopped working and been lost due to IRD. However, no stem cell treatments are currently approved for IRDs.
• Electrical stimulation therapy. Early investigations have looked into whether the degeneration of retinal cells in an IRD can be slowed down using electrical stimulation via the cornea at the front of the eye. There is still much to learn about this approach and further research is still needed. Currently, there is very little evidence that electrical stimulation works to protect retinal cells.
• Nutrition. For most IRDs, there’s no evidence that suggests taking vitamin supplements or having a particular diet will help you avoid sight loss. However, there are exceptions to this for some specific IRDs. If you have an IRD, any questions you have on supplements or diet should be discussed with your GP and ophthalmologist.
• Technology known as artificial vision. Artificial vision systems within the retina and the brain are still being investigated. There isn’t a system which can be easily implanted, and which returns high levels of vision. No artificial systems are currently available on the NHS.

Making the most of your sight

Having a progressive IRD means that you’ll slowly lose sight over time, but there are things that you can do to make the most of your remaining vision. This may mean making things bigger if your central vision is affected. However, if your peripheral vision is very restricted leaving only a limited area of reasonably good central vision, you may prefer to make things smaller so that the detail of your near task is more accessible. In addition, using brighter lighting or using contrasting colours can help make things easier to see.

Low vision assessment

A low vision assessment can help you make the most of your vision. You can ask your ophthalmologist, optometrist or GP about having a low vision assessment. During this assessment, a low vision practitioner can explore equipment, aids or techniques that can help you make the most of your vision. This might be with magnifying aids, using lighting in the right way, or using contrasting colours to help make things easier to see.

Light sensitivity

Light sensitivity (also known as photophobia) often affects people who have an IRD. There are different ways to manage light sensitivity such as wearing a hat with a brim or wearing sunglasses, tinted eye shields or wrap around shades. Your optometrist or low vision specialist can advise you about the lens types that may work best for you.

Assistive technology

There is also technology available that can help with low vision. Many smart phones and tablets are already equipped with in-built software that can enable people with low vision to access information. There are also specific apps and low vision devices that may help too, as well as computer software programmes that can be installed. If you would like to find out more about the assistive technology that is available and how it can help you, our digital skills advisors would be happy to chat to you. You can get in touch with them by calling our Helpline on 0303 123 9999.

Registration

You can ask your ophthalmologist whether you’re eligible to register as sight impaired (SI, previously referred to as partially sighted) or severely sight impaired (SSI, previously referred to as blind). Registration can open up a host of benefits, including help from social services to help you remain independent, as well as financial concessions. Even if you aren’t registered, a lot of this support is still available to you.

Social services support

Local social services should be able to give you information on staying safe in your home and getting out and about safely. They should also be able to offer you some practical mobility training to give you more confidence when you are out.

Family and friends

Your family or the people you live with can help you as your vision deteriorates. For example, by keeping your home environment free of obstacles and by putting things away in the same place, so they are easy to find.

Educational support

For children who have sight loss because of an IRD, having the right support at an early age can make a big difference. Your local authority (LA) should have at least one qualified teacher of children and young people with vision impairment (QTVI) to work with you and your child both at home and at school. A QTVI is a qualified teacher who can provide support with development, play, learning and education. At an early stage, ask your local authority to put you in contact with a QTVI. They will support you and your child as soon as a visual impairment is suspected or diagnosed.

Employment support

If your sight loss is affecting you in your job, there are services and support to help you stay in work, such as reasonable adjustments your employer can make and the Access to Work scheme.

Emotional support and counselling services

It’s completely natural to be concerned if you or your child has an IRD and normal to find yourself worrying about the future and how you or your child will manage with a change in vision. It can sometimes be helpful to talk about how you are feeling with someone outside of your circle of friends or family. At RNIB, we can help with our Counselling and Wellbeing team. Your GP or social worker may also find a counsellor for you if you feel this might help.

Eye Care Liaison Officer (ECLO)

Your eye clinic may have a sight loss advisor working alongside the doctors and nursing staff. This advisor may be known as either the Eye Care Liaison Officer (ECLO), the Vision Support Officer or the Early Intervention Support Officer and they are on hand within your hospital or local sight loss charity to provide you with further practical and emotional support about your eye condition or sight loss. To find out if your hospital eye clinic has an ECLO, you can call our Helpline.

Retina UK is a UK charity providing help, information and support to people who are affected by inherited retinal dystrophy.

Watch our Living with retinitis pigmentosa stories