A deficiency in Vitamin A can cause dry eyes, night blindness, corneal ulcers and can even lead to blindness. Vitamin A has also been shown to prevent cataracts and may prevent blindness due to macular degeneration. Vitamin A is an antioxidant that is found in animal sources, such as liver and cod liver oil. Beta-carotene is a carotenoid that your body converts into Vitamin A. Rich sources of beta-carotenoids are orange fruits and vegetables, such as carrots, sweet potatoes and cantaloupe.