[Epidemiological aspects of xerophthalmia in Chad].

An epidemiologic survey by random cluster sampling was carried out in Chad. Its purpose was to evaluate the importance of xerophthalmia. 3.002 children under 10 years of age were surveyed for two different periods: in 1984 after the drought striking the Sahelian zone and in 1985 after a normal crop. Computerization of the results according to nutritional circumstances and geographical distribution demonstrated that avitaminosis is a true Public Health problem, whatever climatic zones, food products and nutritional conditions are. However situation worsens during a drought and calls for an emergency distribution of vitamin A to the most-in-need populations.