A serious eye condition in which vitamin A deficiency causes the cornea to soften, cloud, and eventually ulcerate, potentially leading to blindness. It typically follows prolonged deficiency that first produces night blindness and dryness of the eye surface. Children in regions with poor diets are most vulnerable, and the condition often accompanies protein-energy malnutrition and infections such as measles that deplete vitamin A stores. Treatment requires urgent high-dose vitamin A supplementation, which can reverse early changes but not established corneal scarring. Prevention through vitamin A supplementation programmes, fortification of foods, and diets rich in orange fruits, vegetables, and animal sources has greatly reduced its incidence.