Overview of Retinitis Pigmentosa
Retinitis pigmentosa (RP) is an inherited condition that causes vision loss.
RP affects the light-sensitive tissue lining the back of the human eye, known as the retina. Light brings visual information about the world into the eye through the pupil. Light then strikes the retina, where special photoreceptor cells convert the visual information into electrical pulses. The optic nerve then carries these pulses to the brain, which recognizes the pulses as images.
Retinitis pigmentosa affects how the retina responds to light. There are two types of photoreceptor cells in the retina: rods that detect dim light and cones that detect light and color. Most forms of RP start with the breakdown of rods; degeneration of the rods lead to night blindness.
Cause of Retinitis Pigmentosa
RP is not the result of infections, injuries or other external or environmental cause. Retinitis pigmentosa is a genetic condition, passed down through families. The National Human Genome Research Institute says that most cases are the result of recessive genes, so a person with RP inherited the gene from both parents. In some cases, though, someone with retinitis pigmentosa inherits the gene from only one parent. In still other circumstances, a new mutation causes RP in someone who does not have a family history of the condition.
Scientists think several different types of gene mutations, or changes in the genes, may send faulty messages to the photoreceptor cells of the retina. These flawed messages eventually cause the retina to breakdown; the degeneration of these cells causes vision loss.
Symptoms of Retinitis Pigmentosa
Symptoms of RP often begin in childhood. People with the condition tend to lose their vision slowly over the course of years. The type of vision loss and the speed at which vision loss occurs varies from person to person, depending on the form of their condition and other factors. The condition does not usually cause total blindness.
Loss of Night Vision
RP may cause night blindness, which makes it hard to see in low light. People with retinitis pigmentosa may have trouble seeing in movie theaters or other dim rooms. Driving at dusk or at night may be especially difficult. Many people with RP have normal vision during the day. They may find it takes longer for their eyes to adjust to darkness once they start losing their night vision.
Loss of Central Vision
Some people with RP experience loss of central vision, which makes it hard to do detailed tasks, such as reading or threading a needle.
Gradual Loss of Peripheral Vision
People with RP may have “tunnel vision,” which means they do not see well to the sides when looking straight ahead, which means their central vision may be fine. The name “tunnel vision” comes from feeling like you’re looking through a narrow tube or tunnel. Loss of this side vision can cause someone to bump into things due to decreased ability to navigate while walking.
Problems with Colour Vision
Those with retinitis pigmentosa may have trouble seeing different colors.
Doctors can use genetic testing to determine if patients have the genes associated with RP. Doctors use a test known as electroretinography to measure electrical activity in the retina to determine how well it responds to light. Visual field testing determines if RP has affected peripheral vision. Optical coherence tomography (OCT) takes highly detailed pictures of the retina to diagnose and assess the progression of RP.
There is no cure for retinitis pigmentosa, but treatment can help control symptoms and reduce complications of the condition.
Researchers have not yet established a single course of treatment for retinitis pigmentosa, but are working to determine why RP occurs in some families and are hoping to develop treatments based on what they learn. Taking vitamin A palmitate may help some people with RP, according to the American Academy of Ophthalmology.
Eyewear for Retinitis Pigmentosa
Low vision aids can help those with Retinitis Pigmentosa make the most of their remaining sight. For example, eSight is a popular choice among those with Retinitis Pigmentosa. eSight is a low vision eyewear device that functions by stimulating synaptic activity from the remaining photoreceptor function of the user’s eyes. Using a cutting edge camera, smart algorithms, and high resolution screens, the assistive technology can provide the brain with increased visual information to naturally compensate for gaps in the user’s field of view. As a result, eSight makes clearer vision possible, resulting in enhanced vision of up to 7 lines on a doctor’s eye chart.
eSight Users with Retinitis Pigmentosa
Users have been able to see their family’s faces for the first time in decades, resume their hobbies and jobs, and regain confidence in their daily lives. Larry Kupner, blind father and veteran, lives with Retinitis Pigmentosa. With eSight, he was able to see his family’s faces in detail for the first time in 10 years, and now uses his enhanced vision to enjoy his hobbies of exploring and fishing in the great outdoors again. Although legally blind, he can currently read with an astounding 20/40 visual acuity.
What is retinitis pigmentosa?
Retinitis pigmentosa (RP) is an umbrella term for a group of more than 60 genetic conditions that cause vision loss. These conditions damage the retina, which is the light-sensitive layer of tissue lining the interior of the human eye. RP affects the way photosensitive cells in the retina, known as rods and cones, respond to light. It begins by damaging the rod cells, which are responsible for night vision. Next, it damages the cone cells that are responsible for seeing colors and for sharpness of vision.
How common is retinitis pigmentosa?
Retinitis pigmentosa is one of the most common inherited diseases affecting the retina. Somewhere from 1 in 3,500 to 1 in 4,000 people in the United States has retinitis pigmentosa.
What causes retinitis pigmentosa?
RP is the result of mutations in more than 60 genes that lead to malfunction of the rods and cones, which in turn leads to deterioration of the retina itself. While external factors, such as injury or infection, do not cause retinitis pigmentosa, they can affect how quickly the condition progresses.
What are the symptoms of retinitis pigmentosa?
Retinitis pigmentosa can cause a variety of symptoms, including:
- Loss of night vision
- Gradual loss of peripheral vision
- Loss of central vision
- Problems with color vision
How do symptoms progress?
Retinitis pigmentosa is a progressive disease, which means it gets worse over time. Depending on the type of gene mutation causing RP, the progression of the disease can differ between people with retinitis pigmentosa. Some people retain central vision but have a restricted visual field throughout life and into their 50s, for example, while others experience significant vision loss in early adulthood. Eventually, most people with retinitis pigmentosa lose their vision completely.
The first symptoms typically develop during childhood – children with the condition often have trouble getting around in darkness, for example. It can also take longer for their eyes to adjust to changes in light. As damage to the retina reduces their visual field, some people with retinitis pigmentosa trip more often or otherwise seem clumsy. Those with the condition often develop photophobia, which causes them to feel discomfort in bright light conditions.
How do doctors diagnose retinitis pigmentosa?
Doctors use a variety of tests to diagnose retinitis pigmentosa. Genetic testing can reveal whether a patient has the gene mutations associated with the condition. Eye doctors can use a variety of tests, such as electroretinography, visual field testing, and optical coherence tomography (OCT) to determine if RP is affecting vision and to assess the progression of retinitis pigmentosa.
Is there any treatment for retinitis pigmentosa?
Currently, there is no single form of treatment for patients with retinitis pigmentosa. Taking certain vitamins, such as vitamin A palmitate, may help.