What are the other Names for this Condition? (Also known as/Synonyms)
- RP (Retinitis Pigmentosa)
What is Retinitis Pigmentosa? (Definition/Background Information)
- Retinitis Pigmentosa (RP) is a hereditary retinal disorder that causes severe vision impairment
- It occurs due to the degeneration of rod photoreceptor cells in the retina, which are responsible for low-light vision. Studies have shown that mutations in certain genes may be responsible for Retinitis Pigmentosa
- There are many signs and symptoms of Retinitis Pigmentosa. Peripheral vision is affected first, followed by mid-peripheral vision causing tunnel vision, and then central vision leading to eventual blindness in one or both the eyes
- Although treatment studies seem promising for the future, the prognosis for Retinitis Pigmentosa is guarded, due to the lack of cure and progressive nature of the disorder, which is inevitable
Who gets Retinitis Pigmentosa? (Age and Sex Distribution)
- The prevalence rate of Retinitis Pigmentosa is about 1 in 3,000-5,000
- Retinitis Pigmentosa is generally diagnosed between the ages of 9 and 19 years. However, symptoms may not develop for decades following diagnosis
- 75% of individuals with Retinitis Pigmentosa over the age of 30 years are symptomatic
- Both males and females are equally affected
- No racial or ethnic predilection is observed and it affects all world populations
What are the Risk Factors for Retinitis Pigmentosa? (Predisposing Factors)
The risk factors for developing Retinitis Pigmentosa may include:
- Family history of the condition
- Usher’s syndrome
- Kearns-Sayre syndrome
- Refsum disease
- Certain rare systemic diseases
It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one's chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.
Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.
What are the Causes of Retinitis Pigmentosa? (Etiology)
Multiple different genes and mutations are responsible for Retinitis Pigmentosa. Studies have shown that the disorder can run in the families and be inherited through a variety of inheritance modes.
- RP is most commonly inherited in an autosomal-dominant manner
- It can also be inherited in an autosomal-recessive or X-linked manner
Retinitis Pigmentosa is the most common retinal dystrophy observed in the world.
What are the Signs and Symptoms of Retinitis Pigmentosa?
The signs and symptoms of Retinitis Pigmentosa may include:
- Loss of function of rod photoreceptor cells, leading to night blindness
- Peripheral vision loss (only in low-light settings in earlier stages), resulting in tunnel vision
- Decreased contrast sensitivity
- Progressive loss of visual field
- Decreased visual acuity and color vision in later stages
- A small amount of central vision may only remain in later stages (as if looking through a peephole)
- Possible total blindness at end-stage
When a healthcare professional examines the eye with specialized instruments, the following signs may be noted:
- Clumped pigment in the peripheral and mid-peripheral retina, also known as bone-spicule pigmentation
- Small blood vessel attenuation
- Waxy appearance of the optic nerve
How is Retinitis Pigmentosa Diagnosed?
Diagnostic tests of Retinitis Pigmentosa may include:
- Observation of the retina by an eye healthcare professional with special lenses or cameras
- Documentation of family history
- Visual field, visual acuity, and contrast sensitivity tests
- Electroretinography, or ERG, which can detect the functionality of rod photoreceptor cells
- Genetic testing to ascertain the specific genes involved
Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.
What are the possible Complications of Retinitis Pigmentosa?
Complications due to Retinitis Pigmentosa could include:
- Loss of contrast sensitivity leading to decreased quality of vision
- Loss of function of cone photoreceptor cells, leading to loss of color vision and visual acuity
- Cystoid macular edema (swelling of the macula) resulting in altered vision
How is Retinitis Pigmentosa Treated?
The treatment measures of Retinitis Pigmentosa may include the following:
- Vitamin A supplementation to slow the degeneration of rod photoreceptor cells
- Acetazolamide, a drug used to reduce swelling of the macula in the case of cystoid macular edema
- Low vision rehabilitation therapy and aids
- Electronic retinal implant
Gene therapy and stem cells research are being undertaken to help treat the condition more effectively.
How can Retinitis Pigmentosa be Prevented?
- Currently there are no specific methods or guidelines to prevent Retinitis Pigmentosa, as it is an inherited retinal disorder
- Genetic testing of the expecting parents (and related family members) and prenatal diagnosis (molecular testing of the fetus during pregnancy) may help in understanding the risks better during pregnancy
- If there is a family history of the condition, then genetic counseling will help assess risks, before planning for a child
- Active research is currently being performed to explore the possibilities for treatment and prevention of inherited and acquired genetic disorders such as Retinitis Pigmentosa
Regular visits to low vision specialists and support groups are useful for maximizing the remaining vision and quality of life of Retinitis Pigmentosa affected individuals.
What is the Prognosis of Retinitis Pigmentosa? (Outcomes/Resolutions)
- The prognosis of Retinitis Pigmentosa is guarded, since it is a progressive condition that gets worse with time
- In many cases, the prognosis is poor, as severe visual impairment is inevitable
- Visual aids and personalized low vision rehabilitation therapy provided by optometrists specializing in low vision may help individuals optimize their remaining visual acuity and visual field
Additional and Relevant Useful Information for Retinitis Pigmentosa:
- Retinal implants, gene therapy, and stem cells are promising treatment options into the future as some studies suggest
- According to Orphanet, a European based group of organizations, a rare condition is defined as one that affects less than 1 in 2,000 individuals