The exact number of children blind in the world is not known but it is estimated that the figure is approximately 1.4 million, with up to 500,000 new cases every year.
Many of these children die within months after they become blind.
The frequency and causes of blindness vary widely in different parts of the world: in Africa and parts of Asia, up to 15/10,000 children are blind, compared to 3/10,000 children in Europe and North America; nutritional factors and infections are more common in developing countries, whereas hereditary factors, developmental disease and the consequences of prematurity are more frequent causes in countries with better standards of living and health care services.
A careful history should be taken, preferably from the mother who has had the closest contact with the child. Visual acuity should be assessed, and the findings recorded. Children over the age of 5 years can usually be tested with a Snellen E chart (top left), but children younger than this need to use other tests, such as pictures or matching methods. In very young children, a history from the parents and observation of the infant can help in determining whether the child is blind or not.
In some children, eye disease will be immediately obvious although this will not always be the case. The cause of the eye condition may be due to infection (top right) which in this child was beginning to improve with intensive topical antibiotics.
Worldwide, vitamin A deficiency is the commonest single cause of blindness in children, accounting for an estimated 350,000 new cases each year. Vitamin A deficiency is also very important as it is associated with higher infant and childhood mortality rates, particularly associated with measles. It is estimated that 60% to 80% of children who become blind from vitamin A deficiency die within a few years because of increased susceptibility to infection and sometimes lack of care.
