Theme: iWiki Log in Register

Diff: Retinitis pigmentosa

Comparing revision #1 (2024-04-26 18:34:02) with revision #2 (2026-06-22 09:09:10).

Old	New
'''Retinitis pigmentosa''' (RP) is a group of [[Genetic disorder\|genetic disorders]] characterised by progressive degeneration of the retina, leading to vision loss and, in severe cases, blindness. The condition affects approximately 1 in 4,000 people worldwide and is a leading cause of inherited blindness.
	'''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 ==
The onset and progression of symptoms in RP can vary widely among individuals and are dependent on the specific genetic mutation involved. Common symptoms include:
	Symptoms often develop gradually. The age at which they start depends on the genetic cause and the pattern of inheritance.

# Night blindness: Many individuals with RP experience difficulty seeing in low light conditions, such as at night or in dimly lit environments.
# Tunnel vision: As the condition progresses, peripheral vision may become progressively constricted, leading to tunnel vision.
# Decreased visual acuity: Some individuals may experience a gradual decline in central vision, making it difficult to read, drive, or recognise faces.
# Photopsia: Some people with RP report seeing flashes of light or shimmering spots in their visual field.
	Common symptoms include:

== Causes ==
RP is primarily caused by mutations in genes that are essential for the function and maintenance of photoreceptor cells in the retina. These mutations can affect various aspects of retinal function, including the production of photoreceptor proteins, the structure of photoreceptor cells, and the health of the retinal pigment epithelium.
	* 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 inheritance pattern of RP can be autosomal dominant, autosomal recessive, or X-linked. In autosomal dominant RP, only one copy of the mutated gene is necessary to cause the disorder, while in autosomal recessive RP, two copies of the mutated gene are required. X-linked RP primarily affects males and is caused by mutations in genes located on the X chromosome.
	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 ==
Diagnosing RP typically involves a comprehensive eye examination, including visual acuity testing, visual field testing, and imaging of the retina. Genetic testing may also be recommended to identify specific mutations associated with the condition.
	Diagnosis is usually made by an ophthalmologist, often with retinal imaging and specialist tests.

== Treatment ==
As of now, there is no cure for RP. However, several treatment options may help manage symptoms and slow disease progression:
	Assessment may include:

# Low-vision aids: Devices such as magnifiers, telescopic lenses, and electronic magnification systems can help individuals with RP make the most of their remaining vision.
# Gene therapy: Emerging treatments, such as gene therapy, aim to address the underlying genetic mutations responsible for RP. These therapies show promise in preclinical and early clinical trials.
# Retinal implants: Retinal prosthetic devices, such as the Argus II Retinal Prosthesis System, can partially restore vision in individuals with advanced RP by bypassing damaged photoreceptor cells and directly stimulating the remaining retinal cells.
# Clinical trials: Many research institutions and pharmaceutical companies conduct clinical trials to evaluate new therapies for RP. These trials may involve gene therapy, stem cell therapy, or novel pharmacological interventions.
	* 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.

== Prognosis ==
The prognosis for individuals with RP varies depending on the severity of the condition and the specific genetic mutations involved. While RP generally leads to progressive vision loss, the rate of progression can be unpredictable. Some individuals may retain useful vision well into adulthood, while others may experience significant vision loss at a younger age.
	Genetic testing can help identify the cause, guide family counselling, and determine whether a person might be eligible for a specific treatment or trial.

== Support and Resources ==
Living with RP can present significant challenges, both physically and emotionally. Support groups, counseling services, and resources for individuals with visual impairments can provide valuable support and information to help individuals cope with the condition and maintain independence.
	== 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.

Retinitis pigmentosa is a complex genetic disorder that causes progressive vision loss due to degeneration of the retina. While there is currently no cure for RP, ongoing research offers hope for future treatments that may slow or halt disease progression and improve quality of life for affected individuals. Early diagnosis, regular eye examinations, and access to supportive resources are crucial for managing RP and maximising visual function.
	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 ==
	* [[Retina]]
	* [[Genetic disorder]]
	* [[Megalocornea]]
	* [[CHRDL1]]

	== References ==
	* [https://www.rnib.org.uk/your-eyes/eye-conditions-az/retinitis-pigmentosa/ RNIB: Retinitis pigmentosa and inherited retinal dystrophies]
	* [https://www.rcophth.ac.uk/wp-content/uploads/2020/05/Understanding-Retinitis-Pigmentosa_2017.pdf Royal College of Ophthalmologists: Understanding retinitis pigmentosa]
	* [https://my.clevelandclinic.org/health/diseases/17429-retinitis-pigmentosa Cleveland Clinic: Retinitis pigmentosa]

	[[Category:Medicine]]
	[[Category:Ophthalmology]]
	[[Category:Genetics]]