Xerophthalmia and night blindness for the assessment of clinical vitamin A deficiency in individuals and populations

Overview

This document aims to provide users of the Vitamin and Mineral Nutrition Information System (VMNIS) with information about the use of xerophthalmia and night blindness for assessing the prevalence of vitamin A deficiency in populations. It is a compilation of the current World Health Organization (WHO) recommendations on the topic and summarizes, from the documents described below, the assessment of night blindness, criteria for defining the degree of a public health problem of xerophthalmia and vitamin A deficiency, and the chronology of their establishment.

The methods and criteria included in this summary are useful for identifying populations most at risk for vitamin A deficiency and in need of intervention. Assessment of the prevalence of xerophthalmia and night blindness permits monitoring of trends in vitamin A deficiency, as well as evaluation of the impact of interventions.