Vitamin A, also known as retinol, is essential to the formation of visual purple in the retina, which allows vision in dim light. Beta carotene, the precursor to vitamin A found in vegetables, has antioxidant properties, meaning it protects cells from the toxic damage of oxidation.
Reviewed last on: 3/7/2009
Linda Vorvick, MD, Family Physician, Seattle Site Coordinator, Lecturer, Pathophysiology, MEDEX Northwest Division of Physician Assistant Studies, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.