Vitamin A deficiency (Q39911)

Vitamin A deficiency (VAD) is defined as a state in which tissue concentrations of vitamin A are low enough to have adverse health consequences even if there is no evidence of clinical xerophthalmia. The term xerophthalmia encompasses the clinical spectrum of ocular manifestations of vitamin A deficiency, from milder stages of night blindness and Bitot’s spots, to potentially blinding stages of corneal xerosis, ulceration and necrosis (keratomalacia). In addition to the specific signs and symptoms of xerophthalmia and the risk of irreversible blindness, nonspecific symptoms include increased morbidity and mortality, poor reproductive health, increased risk of anaemia, and contributions to slowed growth and development.