Retinitis pigmentosa (RP) is a group of inherited retinal disorders in which light-sensitive cells in the retina gradually stop working. It is one of the most common groups of inherited retinal dystrophies.
RP usually affects rod cells first. Rod cells help with night vision and peripheral vision. Cone cells, which support central vision, colour vision, and fine detail, are often affected later.
Retina Background
The retina is the light-sensitive layer at the back of the eye. It contains rods and cones, which convert light into signals that pass through the optic nerve to the brain.
Rod cells are concentrated more heavily in the peripheral retina and are important for seeing in dim light. Cone cells are concentrated in the macula and are important for reading, recognising faces, seeing colour, and detailed central vision.
In RP, genetic changes disrupt the maintenance or function of retinal cells. The exact genes involved vary between families and individuals.
Symptoms
Symptoms often develop gradually. The age at which they start depends on the genetic cause and the pattern of inheritance.
Common symptoms include:
- Night blindness or difficulty seeing in dim light.
- Slow adaptation when moving between bright and dark places.
- Loss of peripheral vision.
- A narrowing field of vision, sometimes described as tunnel vision.
- Increased glare or light sensitivity.
- Difficulty seeing steps, kerbs, doorways, or objects at the side.
- Reduced central vision in later stages for some people.
- Flashing lights or visual disturbances, especially where sight loss is advanced.
The rate of progression varies. Some people retain useful central vision for many years, while others develop more severe sight loss earlier.
Inheritance
RP can be inherited in several ways:
- Autosomal dominant inheritance, where one changed copy of a gene can cause disease.
- Autosomal recessive inheritance, where both copies of a gene are changed.
- X-linked inheritance, which often affects males more severely.
- Mitochondrial or more complex inheritance in some rare cases.
Some people have no known family history. This can happen because of recessive inheritance, a new genetic change, incomplete family information, or mild disease in relatives.
Diagnosis
Diagnosis is usually made by an ophthalmologist, often with retinal imaging and specialist tests.
Assessment may include:
- Visual acuity testing.
- Visual field testing.
- Dilated retinal examination.
- Optical coherence tomography.
- Fundus photography or autofluorescence imaging.
- Electroretinography, which measures retinal electrical responses.
- Genetic testing where available and appropriate.
Genetic testing can help identify the cause, guide family counselling, and determine whether a person might be eligible for a specific treatment or trial.
Treatment and Management
There is no single cure for most forms of RP. Management focuses on preserving useful vision where possible, treating complications, supporting independence, and identifying people who may benefit from gene-specific therapy or research.
Support can include:
- Regular ophthalmology review.
- Low-vision assessment.
- Lighting and contrast adjustments.
- Magnifiers, screen readers, mobility training, and assistive technology.
- Sunglasses, hats, or filters for glare and light sensitivity.
- Treatment of associated cataract, macular oedema, or other eye problems if present.
- Genetic counselling.
RNIB notes that a gene therapy treatment is available on the NHS for an inherited retinal dystrophy associated with RPE65, but most inherited retinal dystrophies still have no routine cure. Research continues into gene therapy, gene editing, cell therapy, retinal prostheses, and other approaches.
Living With RP
RP can affect education, work, driving, reading, independent travel, and emotional wellbeing. Because the loss is often gradual, practical adaptations may be needed more than once as vision changes.
People with RP may be eligible for sight impairment registration, low-vision services, workplace adjustments, travel support, and specialist advice. Early referral to low-vision and mobility support can make daily life easier before sight loss becomes severe.
See Also
References
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