Retinitis pigmentosa (RP) is a group of rare diseases affecting the retina and leading to vision loss over time. Early symptoms include decreased night vision.
The gene mutations involved in RP can pass from one or both parents to a child or can be sporadic, meaning there is no identifiable family history.
The following article describes what RP is and explains its causes, symptoms, treatments, and more.
RP refers to a group of rare genetic disorders that affect the retina, the tissue located at the back of the eye.
The retina contains cells called photoreceptors, which absorb and convert light into electric signals. These signals then travel to the brain via the optic nerve so the brain can process them into the images a person sees.
Photoreceptors consist of rods and cones. Rods are responsible for a person’s vision in low-light situations. Cones help a person see colors and details.
At first, RP affects the rods, causing issues with night vision. As the rods become more damaged and die off, RP begins to affect the cones, further damaging a person’s sight.
The National Eye Institute (NEI) states that RP affects
RP is a progressive condition, which means it generally gets worse over time. Symptoms typically appear during childhood. As RP advances, a person may notice new or worsening symptoms that affect their vision.
- trouble adjusting to changes in lighting
- photophobia, or sensitivity to bright light
- trouble seeing in a darkened room
As the condition progresses and cones also begin to die off, a person will experience a gradual loss of visual field and develop tunnel vision. Eventually, a person living with RP will lose most of their sight.
RP progression can vary significantly between people. Some may experience vision loss at an early age, and others may retain their central vision well into their
RP is a genetic condition. It can occur due to a mutation in over
According to the
Autosomal recessive inheritance
When two people carrying certain recessive gene mutations have a child, there is a:
- 1 in 4 chance the child will develop RP
- 1 in 2 chance the child will become a carrier of RP
- 1 in 4 chance the child will not develop or become a carrier of RP
Autosomal dominant inheritance
When a biological parent carries the gene mutation on the dominant version of a gene, the child only needs one copy of the mutation to develop RP. This gives them a 1 in 2 chance of developing the condition.
This means that the mutated gene is on the X chromosome. Typically, males have one X chromosome while females have two. Females do not develop the condition from X-linked RP because the second X chromosome cancels the effect out.
When a female birth parent is a carrier of X-linked RP, a male child has a 1 in 2 chance of developing RP, and a female child has a 1 in 2 chance of becoming a carrier.
An experienced ophthalmologist can help diagnose RP. Tests that can both diagnose and measure the severity of RP include:
- Electroretinography: This test measures the electrical activity of the eye to see how well the retina responds to light.
- Genetic testing: The person gives a tissue or blood sample to check for a responsible gene and gauge the potential for gene therapy success.
- Optical coherence tomography: This takes a high-resolution picture of the retina for diagnosis and to determine how RP is affecting the person’s eye, particularly the macula, which is responsible for central vision.
- Visual field testing: This looks for and measures blind spots in a person’s vision.
There is currently no cure or single recommended course of treatment for RP.
A doctor may recommend the following to help people manage the condition:
- Eye drops: Dorzolamide drops may reduce swelling from macular edema.
- Medication: Acetazolamide (Diamox), a diuretic medication, may also help with macular edema.
- Surgery: If a person with RP develops cataracts, cataract surgery may help improve vision.
Researchers are working to find out more about the genes that cause RP. The goal is to develop interventions based on the person’s genes that may stop or reverse the condition’s progression.
Studies of new treatments are also underway, including a clinical trial to evaluate the effect of injections of autoserum on people with RP.
According to the American Academy of Ophthalmology, there is some evidence that vitamin A may slow the progression of RP. However, they note that this is not a widely recommended treatment, and too much vitamin A can worsen other eye conditions.
They recommend that people with low vision begin a vision rehabilitation process. Specialized professionals may be able to help, providing services such as occupational therapy. The American Foundation for the Blind also offers various resources for adults new to vision loss.
A person living with RP will experience vision loss over time. The rate of progression and amount of vision loss can vary between people.
- The autosomal recessive form of RP can lead to an early onset of symptoms and cause severe night blindness and vision loss.
- X-linked recessive RP is associated with the most severe vision loss.
- The autosomal dominant form is the least severe. It can lead to a gradual onset of symptoms later on once a person reaches adulthood.
All forms will lead to tunnel vision, and most people with RP become legally blind at some point. However, total vision loss is uncommon.
A person living with RP should speak with a healthcare professional to develop a plan to manage their vision loss and potentially slow the condition’s progression.
A person should speak with a doctor if they notice a slow loss of night or peripheral vision. These can be signs of RP onset. They should also contact a doctor if they experience a sudden loss of sight, as this could be a sign of other conditions.
A person living with RP or who may be a carrier may wish to consider speaking with a doctor about genetic testing. This can help them determine the likelihood that any children they may have will develop the condition.
RP is a progressive collection of diseases that cause damage to the retinas and vision loss. One or both birth parents may pass RP to a child. The progression of the condition can vary significantly between individuals.
Early symptoms typically include difficulty with night vision and a loss of peripheral vision. As the condition progresses, it can lead to vision loss and blindness.
There is currently no cure for RP, but a person can find ways to adjust to their vision loss. A doctor can provide advice and resources.