The periodicity of xerophthalmia in South and East Asia

Abstract

Many factors are responsible for the onset of demonstrable eye pathology in hypovitaminosis A. These factors apply equally to the child as a single person or as a member of a population group. Besides a marginal vitamin A status, the most common factors are protein calorie malnutrition, both of the kwashiorkor and marasmic varieties, and the diarrhoea and infectious diseases of childhood. In this study, the incidence reported from four ophthalmic hospitals in Vietnam, India and Indonesia, is analysed. Although there were irregular annual fluctuations in incidence, a regular perennial pattern was present in all four locations. Two annual peak periods occurred in Hanoi, and one in Bangalore, Sourabaya and Bandung. It is suggested that the sinusoidal incidence pattern in Sourabaya and Bandung was connected with climatological variation, especially solar radiation. Periodicity in the incidence of xerophthalmia may point to fluctuations or tides in retinol levels in the serum of the child population. Waves of xerophthalmia or a definite seasonal prevalence are important and must be taken into consideration in surveys directed at determining vitamin A status. If xerophthalmia waves are predictable, preventive measures such as the periodic massive dosing of vitamin A by mouth should be implemented at the most appropriate time for them to be optimally efficacious.