Choroideremia
A rare inherited retinal disease that causes progressive degeneration of the retina, retinal pigment epithelium, and choroid — the layers of the eye that support healthy vision.
Understanding Choroideremia
Choroideremia is a rare inherited retinal disease characterised by the progressive degeneration of the retina, retinal pigment epithelium (RPE) and choroid, the layers of the eye that support healthy vision.
The condition is caused by changes in the CHM gene, which affect the normal function and survival of retinal cells. It primarily affects males and typically begins in childhood or adolescence with difficulty seeing in low light (night blindness), followed by a gradual loss of peripheral (side) vision. As the condition progresses, the visual field may become increasingly restricted, although many people retain useful central vision into adulthood.
The onset and progression of vision loss vary between individuals. Choroideremia is an important focus of gene therapy research, with clinical studies helping to advance understanding of genetic treatments and potential approaches to preserving or restoring vision.
Retina International works with people affected by Choroideremia, patient organisations, researchers, clinicians and partners worldwide to accelerate research, strengthen patient involvement and improve outcomes for people living with inherited retinal diseases.
1 in 50,000–100,000
Estimated prevalence
1
Identified gene
100%
X-linked inheritance
How Choroideremia can affect vision
Night blindness
Difficulty seeing in dim light or adapting from bright to dark environments is often one of the earliest signs.
Loss of peripheral vision
Progressive narrowing of side vision may affect mobility and awareness of surroundings.
Reduced visual field
Over time, people may experience tunnel vision as peripheral vision decreases.
Reduced central vision
In later stages, central vision may become affected, impacting reading and detailed tasks.
Light sensitivity
Some individuals experience discomfort or difficulty in bright environments.
Identifying Choroideremia
Eye examination
An eye care professional (an optometrist or an ophthalmologist) will examine the retina and assess changes associated with Choroideremia.
Visual field testing
Visual field testing measures how much of your surroundings you can see while looking straight ahead and helps track changes in your vision over time.
Retinal imaging
Special scans (Optical coherence tomography) and photographs ( fundus photography) of the retina help doctors see changes at the back of the eye.
Electroretinography (ERG)
This test measures how well the cells in your retina respond to light and helps assess retinal function.
Genetic testing
Genetic testing can identify mutations in the CHM gene and confirm the diagnosis. The results can help explain how the condition is inherited, guide care, and determine whether you may be eligible for research studies or clinical trials.
Supporting vision and exploring emerging therapies
Low vision support
Specialist services can provide:
- Visual aids
- Assistive technologies
- Mobility training
- Strategies for adapting daily activities
Regular eye monitoring
Ongoing monitoring helps assess changes in vision and retinal health.
Genetic counselling
Genetic counselling can help individuals and families understand inheritance, family planning options, and testing decisions.
Emerging therapies
Because Choroideremia is caused by a mutation in a single gene, it has been a major focus for gene therapy research.
Research approaches include:
- Gene replacement therapy
- Retinal cell protection strategies
- Other approaches aimed at preserving retinal function
Adapting to progressive vision loss
Living with Choroideremia involves adapting to gradual changes in vision while maintaining independence, education, employment, and participation in daily life.
Support may include:
- Low vision rehabilitation
- Orientation and mobility training
- Assistive technology
- Workplace and educational adjustments
- Peer support networks
- Patient organisations
Because Choroideremia primarily affects males, families may also need support in understanding inheritance patterns and the potential impact on relatives.
The lived experiences of people affected by Choroideremia are essential in shaping research priorities and improving care.
Advancing the future of Choroideremia treatment
Gene therapy
Researchers are investigating whether delivering a functional copy of the CHM gene can preserve or improve retinal function.
Retinal cell therapies
Retinal cell therapies explore the replacement or regeneration of damaged retinal cells to help restore visual function.
Retinal prostheses and vision restoration technologies
Retinal prostheses and vision restoration technologies use innovative devices and technologies to stimulate remaining retinal pathways and support vision.
Natural history studies and registries
Natural history studies and registries collect long-term data to better understand how this disease progresses and to guide future treatment development.
Clinical trials
Clinical trials evaluate the safety and effectiveness of new therapies, medicines, and technologies for people living with this disease.
Information and community support
Take the Next Step
Choroideremia has played an important role in advancing gene therapy research and demonstrating the potential of precision approaches for inherited retinal diseases.
Through collaboration between patients, researchers, clinicians, and organisations worldwide, progress continues towards a future where people affected by Choroideremia have access to earlier diagnosis, improved support, and effective treatments.
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