Retinitis Pigmentosa (RP) is a group of inherited retinal disorders characterised by the progressive degeneration of photoreceptor cells in the retina. This condition typically manifests as night blindness and tunnel vision, gradually leading to severe vision impairment or blindness.
What is the biology of RP?
- Genetic Basis:
RP is primarily caused by genetic mutations that impact the function and survival of photoreceptor cells. Various genes can be involved, and the inheritance pattern can be autosomal dominant, autosomal recessive, or X-linked.
- Photoreceptor Degeneration:
The disease often starts with the degeneration of rod cells, specialised for low-light vision. As rod cells diminish, individuals experience night blindness. Subsequently, cone cells, responsible for central and colour vision, are affected, resulting in a loss of central and peripheral vision.
- Retinal Pigment Epithelium (RPE) Changes:
One of the layers in the retina, nearer the bottom is called the retinal pigment epithelium. Changes in the retinal pigment epithelium (RPE) contribute to the characteristic appearance of “bone spicules” in the retina. Accumulation of pigment granules and degeneration of RPE cells further compromise retinal health.
What types of RP are there?
There are various types of RP that can manifest with different genetic causes. Our team of Genetic specialists will guide you through this information at a consultation and also the benefits of genetic testing to understand which RP you or the patient may have.
- Autosomal Dominant RP (ADRP): accounts for approximately 30-40% of cases and is inherited from one affected parent which is why it is called ‘dominant’ i.e. only one copy of the mutated gene is required for the disease to be present.
- Autosomal Recessive RP (ARRP): Represents about 50-60% of cases and requires both parents to be carriers because of the recessive nature of the mutated gene.
- X-Linked RP (XLRP): this variant affects males mos frequently and involves mutations on the X chromosome.
- Syndromic RP: this is an RP associated with other systemic conditions. Examples include Usher syndrome, Bardet-Biedl syndrome
How common is RP and how does it progress?
The estimated prevalence of RP is approximately 1 in 4,000 individuals worldwide. It is typically diagnosed in adolescence or early adulthood and the rate of vision loss varies, but most individuals experience gradual deterioration over decades.
What are the symptoms of RP?
The following are the most common symptoms of Retinitis Pigmentosa:
- Night Blindness: Difficulty seeing in low-light conditions.
- Tunnel Vision: Gradual loss of peripheral vision, leading to tunnel-like vision.
- Photophobia: Increased sensitivity to light.
- Loss of Central Vision: Impacting detailed and colour vision.
How is RP diagnosed?
At The Retina Clinic London, all patients attending an initial consultation with one of our Genetic Diseases Specialist, will undergo an array of extensive testing to help diagnose your condition whilst will include, amongst others:
- Visual Acuity Tests: Assessing clarity and sharpness of vision.
- Visual Field Tests: Mapping the extent of peripheral vision.
- Electroretinography (ERG): Recording the electrical responses of photoreceptor cells.
- High-resolution Ultrawide-field OCT and Macula OCT: Cross-sectional scans of your retina will be taken to identify which changes are happening at an anatomical level in your retinas and to know the extent of any existing conditions.
- Ultra-widefield multi-wavelength fundus images: pictures of the back of your eye will be taken to have an en-face view of your retinas and to see the extent of any disease and to understand where the affected areas are.
- Genetic Testing: at The Retina Clinic London, we are in the privileged position of being able to offer a genetic testing service with samples collected in-house before being sent off to the laboratory for processing. This genetic testing is specifically to identify any mutations in those genes associated with the retina and its functioning. We also offer a service to test family members to see if there are also carriers of that gene. More information can be found here.
Ultra-widefield multi-wavelength fundus image of an eye with retinitis pigmentosa
What available treatment options are there for RP?
At the moment there are no approved treatments options for RP in adults. However, at The Retina Clinic London, we are also a centre for industry-sponsored clinical trials and, led by Prof. Stanga, we aim to bring patients choice in signing up to the latest trials for their condition where possible. Please see our Clinical Trials page to understand whether or not we are currently recruiting for a trial in RP. Similarly, following a consultation with us, with your consent, you will automatically be entered into our database to be contacted for future studies.
Low Vision Aids are an option for managing the symptoms of RP and include devices like magnifiers, telescopes, and adaptive technologies to enhance remaining vision. These can be discussed in further detail during your consultation.
Coping with RP
When attending a genetics consultation at our clinic, our specialists will discuss with you to variety of emotional and psychological resources to cope with RP and the disease progression. These will include:
- Genetic Counselling: Guidance for families on the inheritance pattern and risk.
- Support Groups: Connecting with others facing similar challenges.
- Orientation and Mobility Training: Learning techniques for safe navigation.
- Psychosocial Support: Addressing the emotional impact of vision loss.