No one wants to hear that their vision is going to get worse. If you've just found out you have retinitis pigmentosa (RP), you're likely wondering what to expect.
While each case is different, we know a lot about how RP progresses. RP refers to a group of inherited eye diseases that lead to severe visual problems. There are several treatment and preventive options that can help those who may be at risk.
What Is Retinitis Pigmentosa?
Your retina converts what you see into signals that are sent to the brain. When light-sensitive cells break down, vision loss occurs.
The name comes from irregular clumps of black pigment seen in the retina with this disorder.
What Causes RP?
Most types of RP are caused by a genetic mutation. But some other cases occur sporadically.
RP can affect either the cone shaped cells or the rod shaped cells in your retina.
The cone cells in your retina give you central vision and allow you to see colors.
The rods are what allow you to see at night and have peripheral vision.
Most forms of retinitis pigmentosa affect the rod cells. This causes night blindness and poor peripheral vision (tunnel vision).
When the cone cells are affected, central vision and color vision are affected. The vision loss is usually gradual, and progresses over years.
Does Viagra Cause Retinitis Pigmentosa?
While sildenafil (Viagra) doesn’t cause RP, it can cause vision loss for those who are carriers of the gene. If you have a family history of RP, it’s important to discuss that with your doctor before starting new medications.
Risk Factors for Retinitis Pigmentosa
The two major risk factors for RP are having family history of the condition or being male.
What Are the Symptoms of Retinitis Pigmentosa?
Vision loss is usually first noted in childhood or early adulthood. As the disease worsens, vision loss becomes more noticeable. Fortunately, while progressive, RP is slow. And most patients never completely lose their vision.
Due to extremely limited peripheral vision, many patients are considered "legally blind."
Overall, symptoms may include:
- Night blindness
- Trouble adjusting to light changes or dim lighting
- Difficulty seeing in bad weather
- Tunnel vision caused by narrowed peripheral vision
- Trouble seeing colors, especially blue
- Vision loss, partial or complete, usually gradual
- Clumsiness due to poor vision
- Blurry vision from cataracts may complicate RP later in the disease
How Is Retinitis Pigmentosa Diagnosed?
Your doctor will ask about your symptoms and medical history, and perform an eye exam. You may be referred to an eye specialist, such as an ophthalmologist.
Vision tests may include:
- Visual field testing—to check peripheral vision
- Visual acuity—checks how well you can see progressively smaller objects, usually a row of letters or numbers
- Dark adaptometry—tests how your vision adapts to darkness
- Color testing—determines how well you can differentiate colors
- Electroretinogram (ERG)—a test to measure electrical activity in the eye. This test identifies the loss of cell function in the retina and is used to track progression of the disease.
What’s The Treatment for Retinitis Pigmentosa?
There is no effective treatment or cure for RP. Treatment aims to help you function with the vision you have. Your doctor can counsel you about expected patterns of vision loss based on the type of RP you have. Recommendations include:
One study implied that large doses of vitamin A can slow the progression of RP by approximately 2% per year. However, the use of this finding is controversial. For one, it is a very mild effect given the large dose. Secondly, there may be side effects of such large doses of vitamin A. Always talk to your doctor before taking any supplements.
Although no direct link has been established, it is generally recommended that everybody, especially patients with disorders such as RP, wear dark UV-protected sunglasses and a wide-brimmed hat in bright, sunny conditions, such as while skiing or at the beach.
These may include the following:
- Magnifying glasses
- Electronic magnifiers, which project an enlarged image onto a screen
- Night vision scopes, which enlarge distant objects under conditions of low light
- Eye glasses or contacts
Some community organizations offer classes to help people with vision loss adjust and learn how to use vision aids. If you are considered legally blind, you are entitled to many low-vision services at no cost.