Nutritional blindness in Africa.

Nutritional blindness is loss of useful vision resulting from vitamin deficiency. A malnutrition Xerophthalmia means all the ocular manifestations of inadequate metabolism of vitamin A, nutritional blindness being the end result of the most severe cases. The estimated overall prevalence of nutritional blindness in Africa is very low, below the WHO levels of significance, although isolated clusters of locally high prevalence exist, usually in arid, sparsely-populated regions. The peak age group affected is 2-year olds, with most nutritional blindness having its effect before age 6 years. Xerophthalmia may be considered as a serious side effect of protein-energy malnutrition (PEM). When associated with corneal sequelae of xerophthalmia, PEM has an estimated overall mortality of 50%. Intervention programs, therefore, are more appropriately aimed at the broader condition of life-threatening PEM than at the specifically vision-threatening problem of xerophthalmia. Parameters of significant prevalence detection are discussed, and the relative merits of different forms of vitamin A-specific intervention programs are weighed.