Although optic neuritis occurs relatively infrequently in childhood, it may be a complication of measles, 23 mumps, 34 chicken pox, 8 or pertussis; 12 isolated instances have been reported following a wide variety of infectious diseases including those due to protozoa. 10 It may also follow immunization procedures. 3,16 Hereditary forms may result in severe visual impairment dating from birth or may cause visual failure at almost any age. 13,18,25 While the majority of these are not associated with involvement of other parts of the nervous system, some may be one manifestation of a familial or hereditary degenerative disease of the nervous system. 31 Malnutrition of a severe degree has been found to be associated with visual failure and partial optic atrophy in children in the British West Indies, 2 but to date no cases have been seen in this country. Certain toxic agents and a number of drugs listed