Mass distribution of vitamin A and the prevention of keratomalacia

Measles blindness

Measles remains a major problem in developing countries, where it affects an estimated 30 million children a year and causes up to one million deaths annually. Measles blindness is the single leading cause of blindness among children in low income countries, accounting for an estimated 15,000 to 60,000 cases of blindness per year. There is a close synergism between measles and vitamin A deficiency that can result in xerophthalmia, with corneal ulceration, keratomalacia, and subsequent corneal scarring or phthisis bulbi. High-dose oral vitamin A supplementation is recommended for all children with measles in developing countries. Higher measles immunization coverage to interrupt measles transmission and interventions aimed at improving vitamin A nutriture of children are the main strategies to prevent measles blindness.

Increased mortality in children with mild vitamin A deficiency

An average of 3481 preschool-age rural Indonesian children were re-examined every 3 months for 18 months. The mortality rate among children with mild xerophthalmia (night blindness and/or Bitot's spots) was on average 4 times the rate, and in some age groups 8 to 12 times the rate, among children without xerophthalmia. Mortality increased, almost linearly, with the severity of mild xerophthalmia (night blindness, Bitot's spots, and the two combined). These relations persisted after stratification for respiratory disease, wasting, gastroenteritis, pedal oedema, and childhood exanthems. Mild vitamin A deficiency was directly associated with at least 16% of all deaths in children aged from 1 to 6 years. These results suggest that mild xerophthalmia justifies vigorous community-wide intervention, as much to reduce childhood mortality as to prevent blindness, and that night blindness and Bitot's spots are as important as anthropometric indices in screening children to determine which of them need medical and nutritional attention.

Xerophthalmia and anterior-segment blindness among preschool-age children in El Salvador

A countrywide prevalence survey of 9,508 children was conducted in El Salvador to determine the prevalence of anterior-segment abnormalities and magnitude of clinical vitamin A deficiency. Thirty-six children had corneal opacities, 56% of them secondary to trauma. Such traumatic corneal opacities were 19 times more frequent among urban than rural children, 57.6 vs. 3.1 per 1,000. Keratomalacia accounted for only 8% of all corneal opacities, and for one (and possibly two) of the five cases of bilateral anterior-segment blindness encountered. The prevalance of Bitot spots and vitamin-A-related corneal opacities was 5.3 and 3.2 per 10,000, respectively. There are an estimated 43 new surviving cases of vitamin-A-related corneal opacities in the country each year, one third of which result in bilateral blindness. Fifteen percent of all children examined had grossly purulent conjunctivitis.