RESUMEN
PIP: Vitamin A deficiency and xerophthalmia are among the most widespread human nutritional problems worldwide. High levels of vitamin A deficiency are seen especially among disenfranchised populations where young children are the most severely affected, leading to blindness and early mortality. Not seen in the industrialized countries since the 1950s, vitamin A deficiency still exists in Africa, Asia, and South America. There are approximately 10 million new cases of xerophthalmia per year, of which 280,000-500,000 are blinded. For 20 years, international organizations, governments, and private concerns have found such deficiency with some, but not complete, success. The authors describe the metabolism of vitamin A, analyze its ocular manifestations, and consider the epidemiology of vitamin A deficiency, its association with excess infant mortality, and the course of disease leading to blindness. The global distribution of vitamin A deficiency and xerophthalmia are described. All factors related to vitamin A level in the human body can be changed for the better. Food supplementation with vitamin A and the occasional administration of vitamin A are discussed as possible options to pursue.^ieng