Nutritional Support for Vision and Circulation. Bilberry extract has become the leading herb for the maintenance of healthy vision. Studies with bilberry show that it helps eyes adapt to the dark especially after prolonged exposure to bright light and improves visual acuity in dim light. The active ingredients in bilberry anthocyanosides are a group of flavonoids that increase the production and integrity of collagen a protein that forms connective tissue in the body. All Natural Factors products are manufactured in accordance with the Government of Canada's Good Manufacturing Practices (GMP) among the highest standards in the world.