What Is Retinitis Pigmentosa? Causes, Symptoms & Available Treatments
Retinitis Pigmentosa(RP) affects 1 in 4000 people worldwide. This rare but widespread disorder affects the light-sensitive retina which leads to vision impairment, and eventually, severe vision loss.
Causes of Retinitis Pigmentosa
Most cases of RP are caused by a genetic condition, but some cases are caused by other health problems that affect the retina such as syphilis, rubella, phenothiazine or chloroquine toxicity, and nonocular cancer.
When RP is caused by a genetic disorder, a mutation within the genes stops the gene from making the protein required in the photoreceptor cells in the eye. The photoreceptor cells are responsible for receiving light and colour for the retina, and when these cells don’t have the protein they need, it limits the function and eventually leads to permanently damaged cells.
There are two types of cells around the retina that collect light. The outer rim of the retina has rods that are active in dim light and help with peripheral vision; the inner circle of the retina has cones that help see colour. Signs of RP usually occur in childhood, if there is a known family history of this genetic disorder, families are usually on the lookout for early symptoms.
Symptoms of Retinitis Pigmentosa
Symptoms of RP usually appear in early childhood. At first, adjusting to changes in lighting and seeing in the dark becomes more difficult affecting night vision. Next, the field of vision narrows and sight becomes more impaired; children may trip more or seem clumsy, they may also find bright lights uncomfortable.
However, since this disorder is caused by many different types of gene mutation, the progression can also differ greatly. While, eventually, most people will lose nearly all of their vision, how the disorder develops varies from person to person. Sometimes, central vision or a restricted vision field can be retained up to 50 years of age. In other cases, significant vision loss occurs in early adulthood.
Diagnosing Retinitis Pigmentosa
It is vitally important to get a comprehensive eye exam that can give an accurate diagnosis of RP. This will determine the status of the disease, what options are available, and what low vision treatments or even clinical trials could help maintain as much vision as possible for as long as possible.
A comprehensive eye exam for diagnosing RP would include a funduscopy, which is usually supplemented with electroretinogram, visual field testing or genetic testing.
Retinitis Pigmentosa Treatment
Unfortunately, the damage caused by RP is permanent, but early diagnosis can mean treatments will be more effective in slowing the progression of vision loss.
There are a few targeted therapies for RP, but because there are so many different causes of this disorder, and because progression varies greatly in each person, it can be difficult to predict how effective treatments will be for any one patient.
A recent clinical trial found that a daily dose of 15,000 international units of vitamin A palmitate slowed the progression of the disorder in adults, and dietary supplements of omega-3 fatty acid also slow the progression.
Carbonic anhydrase inhibitors can yield mild improvements in vision for patients with cystoid macular edema, for patients with severe vision loss a visual prosthesis, such as epiretinal and subretinal computer chip implants, may be an option.
For more information on Retinitis Pigmentosa, contact Orchard Park Optometry. We are open seven days a week and will treat you with the highest level of eye care available. To set up an appointment, contact us through our website or call us at 1-250-762-2090.