Childhood blindness

24 Childhood blindness Clare Gilbert & Alien Foster Aperson is declared blind when the corrected visual acuity in the better eye is less than 3/60. These persons cannot see the largest letter of an eye chart (about 9 cm in size) with either eye at a distance of three metres , using spectacles if worn. This definition applies equally to children, although in very young chi ldren other methods of measuring vision may be needed. There is limited information about the proportion of children in the world who are blind. Data from registers of the blind in European countries suggest that two to three children in every 10 000 are affected. In Latin American countries, it is estimated that between four and six children in 10 000 are blind, and in the poorer countries of Asia and Africa the figure is probably in the region of nine to eleven. Using these figures, we can assume that there are 1 500 000 blind children in the world. About 85% live in Asia and Africa, reflecting the higher preva- lence of blindness in those regions as Although blindness in children is relatively uncommon, it poses a heavy burden on the individual, the family and society. Health care workers must be made aware of the need for preventive measures and early identification of children with eye disease. of childhood are also associated with a high mortality rate, e.g. vitamin A deficiency, measles , meningitis and congenital rubella infection. Causes of blindness in children The causes of blindness in children can be classified in two ways. The first is descriptive depending on the part of the eye involved: scarring and opacity of the normally transparent cornea; opacity of the lens of the eye (cataract); atrophy of the optic nerve; well as the large population of children. There is no information on the incidence of blindness - the number of chil- dren in a popula- tion who become blind each year - but it is estimated to be in the order of 500 000 per year. Of these, up to 60% die within one year of be- coming blind, since many of the blinding diseases Teacher and student working with o broille typewriter. World Health • 48th Year, No. 5, September-October 1995 and diseases of the retina. The sec- ond depends on the time of onset of the condition that led to blindness: factors operating at conception (genetic disease); factors operating during pregnancy (e.g. rubella infec- tion, the toxic effects of drugs and alcohol); factors operating around the time of birth (birth injury, con- junctivitis due to sexually transmit- ted diseases , consequences of premature birth) ; and factors acting during childhood (e.g. vitamin A deficiency, measles infection, injury, meningitis) . The main causes of blindness in children, which vary widely between countries and even regions, are largely determined by the level of socioeconomic development and accessibility to preventive and cura- tive health care services. In industri- alized countries the main causes are diseases of the retina, optic nerve and higher visual pathways, due to gen- etic factors or extreme prematurity. Cataract accounts for some 1 0%, and there are very few cases of opacity of the cornea. In countries with low socioeco- nomic develop- ment most blindness is acquired during childhood, and is due to corneal scarring from vitamin A defi- ciency, measles infection, injury and the use of harmful tradi- tional eye prac- tices. Studies in schools for the World Health • 48th Year, No. 5, September-October 1995 25 blindness could have been prevented by measles immunization, preventing or treating vitamin A deficiency, and avoiding the use of harmful eye medicines. Other conditions that can be prevented through primary health care include conjunctivitis of the newborn and congenital rubella infection . This Nepalese boy has just had surgery for congenital cataract. In other countries, infor- mation is less readily available, but there is evi- dence that retinopathy of prematurity is becoming an important cause in some Latin American coun- tries and in urban areas of newly industrializing countries. As a country's socioe- conomic status changes, so the main causes of blindness in children will change. There is Although blindness in children is relatively uncommon, in terms of years of disability, it poses a heavy burden on the individual, the family and society. It is essential to improve awareness among health care work- ers at all levels about the need for preventive measures, and the impor- tance of early identification and referral of children with eye disease. Appropriate training, facilities, equipment and specialist skills are required to manage surgically curable conditions, and to provide low-vision services. • blind show that 30-70% of blindness is due to corneal scarring in African countries and 20-30% in Asian countries. Other causes include congenital abnormalities, cataract and glaucoma. In countries with intermediate levels of socioeconomic development, for instance in Latin America and the Eastern Mediterranean region, the pattern of blindness is mixed, with corneal scarring accounting for 1-20%, cataract for 5-39%, optic nerve disease 8-15% and diseases of the retina 10- 50%. Changing patterns The major causes of blindness in children appear to change over time. In European countries, conjunctivitis of the newborn baby (due to gono- coccal infection) was a common cause at the turn of the century. During the 1950s, retinopathy of prematurity (disease of the retina in low-birth-weight babies) accounted for around 50% of blindness. These conditions are now less important, as a result of antibiotic treatment of sexually transmitted diseases and improved management of low-birth- weight babies. therefore a need to monitor the causes of blindness in children so that appropriate preven- tive or therapeutic strategies can be introduced. Data obtained from examination of children in schools for the blind in Africa, Asia and Latin America suggest that 30-75% of the causes were either preventable, or amenable to sight-preserving or sight-restoring treatment. In Africa and Asia, between a quarter and a half of all Or Clare Gilbert and Mr Alien Foster work at the International Centre for Eye Health , Institute of Ophthalmology, Bath Street, London EC I V 9EL, England World Day for Disabled Persons As a result of a dec ision taken by the United Nations at the end of its Decade of Disabled Persons 1983-92, 3 December every year is marked as the World Day for Disabled Persons. In Europe, the body responsible for organizing it is the European Forum for Disabled Persons. Th e Worl d Day for 1995 is being arranged by three nongovernmental organizations- a ll members of the European Forum - on th e th eme of Full C itizenship. Preparatory sess ions in September dealt wi th four themes, each w ith its own workshop: self-determination for the disabled , integration, non-discrimination, and help for families . Thi s event offers a good opportu ni ty for raising public awareness about disabled persons, the problems they encounter in their daily life, and their demand for ful l citizenship. Member States w ill be invited to ensure good coverage of the event in the public media. Contributed by Paul Bouliner, President of the Conseil franr;:ais des personnes handicapees pour les questions europeennes, and Bruno Gaurier, Director of External Relations, Association des Paralyses de France, 17 Boulevard Auguste Blanqui, 75013 Paris, France.