"Source Naturals Bilberry Extract (Vaccinium myrtillus), also referred to as blueberry, is a potent standardized extract that contains 37% anthocyanosides, a bioflavonoidlike substance that is the active constituent. In vitro studies have demonstrated that anthocyanosides have significant antioxidant activity. Bilberry has been a staple of European herbal therapy for hundreds of years and has become one of the most widely used herbs in the United States for supporting normal vision. "