Vitamin C (also known as ascorbic acid) is a water-soluble vitamin abundant in fruits and vegetables, vitamin C helps the body form and maintain connective tissue, which also exists in the cornea of the eye. Vitamin C also promotes healthy bones, skin and blood vessels, including the delicate vessels in the retina. Studies suggest long-term consumption of vitamin C also may reduce the risk of forming a cataract and vision loss from macular degeneration. Unlike most animals, humans are unable to produce vitamin C in the body. So we must get our daily dose of ascorbic acid from our diet. A diet deficient in vitamin C can lead to a serious disease scurvy which causes muscle weakness among other problems. Excellent natural sources of vitamin C include peppers, citrus fruits, berries, tropical fruits, potatoes, tomatoes and green leafy vegetables.