Which vitamin is primarily associated with vision?

• A. Vitamin A
• B. Vitamin C
• C. Vitamin D
• D. Vitamin K

Answer: (A)

Vision relies on a light-detecting pigment in the retina called rhodopsin, which needs retinal, a form of vitamin A, to form. When vitamin A is deficient, retinal can’t properly combine with the protein to make rhodopsin, so the eye’s ability to respond to low light is impaired. This leads to night blindness and, with prolonged deficiency, surface problems of the eye such as xerophthalmia. Vitamin A also helps maintain the health of the corneal surface, supporting clear vision. You can obtain vitamin A as retinol from animal foods or as provitamin A carotenoids like beta-carotene from colorful fruits and vegetables. The other vitamins have different roles—C in collagen and antioxidant protection, D in calcium and bone health, K in blood clotting—so they aren’t primarily linked to vision.