Retinitis pigmentosa is an incurable disease that causes gradual visual loss in those unfortunate enough to be diagnosed with it. Although the exact cause of this serious eye disease isn’t known, most cases are genetic in origin – and run in families. People with retinitis pigmentosa experience gradual loss of light sensitive cells called rods and cones – which sense light. Rods are more effective at sensing dim light, while cones detect bright light and color. The loss of these light-sensitive cells can result in complete blindness.
What Visual Changes Occur with Retinitis Pigmentosa?
In retinitis pigmentosa the light-sensing rods and cones are slowly and gradually destroyed over time. Since the rods are affected first, people with retinitis pigmentosa usually lose night vision and peripheral vision first. As the disease progresses, cones are also destroyed, which leads to loss of central vision – with complete visual loss over time.
Oral Beta-Carotene for Retinitis Pigmentosa?
According to a recent study presented at the 2010 American Academy of Ophthalmology, taking oral beta-carotene as a supplement can help some people with retinitis pigmentosa regain some of their vision. When they gave oral beta-carotene to 29 different people with retinitis pigmentosa for a period of three months, one out of three experienced some improvement in their ability to see. Unfortunately, the other two-thirds didn’t respond to beta-carotene supplements.
Researchers believe there are certain genetic types of retinitis pigmentosa that improve with oral beta-carotene, while others don’t. They’re planning to do more research to determine what types are the most responsive to beta-carotene therapy.
Why Oral Beta-Carotene?
It’s not surprising that oral beta-carotene benefits people with retinitis pigmentosa. Beta-carotene is a form of pro-vitamin A, meaning a portion of it is converted by the body to vitamin A. Studies show that retinitis pigmentosa sufferers that supplement with 15,000 I.U. of vitamin A per day delay onset of the visual loss that’s so typical of retinitis pigmentosa.
It’s not clear whether all of the benefits of oral beta-carotene come from its conversion to vitamin A. Beta-carotene is a good antioxidant, which may also benefit people with retinitis pigmentosa. Vitamin A is usually found in animal products, while beta-carotene is abundant in orange and green, leafy vegetables. High levels of vitamin A can be toxic, but beta-carotene is usually non-toxic, because only limited amounts are converted to vitamin A.
Oral Beta-Carotene for Treating Retinitis Pigmentosa: The Bottom Line?
Beta-carotene supplements show promise for treating some types of retinitis pigmentosa, although not everyone will benefit beta-carotene supplements. If you have retinitis pigmentosa, talk to your doctor about beta-carotene and vitamin A.
Eurekalert.org. “Beta carotene and retinitis pigmentosa”
Exp. Eye Res. 85 (1): 7-14.
E-Medicine. “Retinitis Pigmentosa: Treatment and Medication”