9-cis Beta-Carotene Mat Boost Vision in Some Patients with Incurable Retinal Disease Retinitis pigmentosa (RP) is a cluster of hereditary disorders of the retina (the light-sensitive tissue at the back of the eye) that can result in incurable blindness. RP usually begins with night blindness in childhood, then loss of peripheral (side) vision leading to tunnel vision, and ultimately blindness. Since a specific form of the nutrient beta carotene, 9-cis, has proven effective against one type of night blindness, researchers decided to test its effects in RP patients. One third of the 29 participating patients showed improved visual function while taking the prescribed oral dose for 90 days, but the other two-thirds showed no effect.
"We recommend repeating the study with patients with the genetic forms of RP that would be most likely to respond to oral beta carotene," said Dr. Rotensteich. "We know its positive effect is associated with retinoid cycle defect, which is involved in some but not all forms of RP. Also, future research should look for the optimal beta carotene dosage," he added.
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