This article provides a survey of the problems of prevention of blindness in developing countries. The World Health Organization estimates that 31 million people are blind and 15 million people partially-sighted. The main cause of blindness is cataract. Other causes are trachoma, glaucoma, xerophthalmia, river blindness, corneal scars and leprosy. Prevention or treatment of these causes is possible in more than 80% of cases. The number of blind persons, however, is still increasing due to the increase in population and the immense shortage of all kinds of ophthalmological equipment and personnel. An effective strategy for the prevention of blindness in developing countries should focus on: more cheap cataract operations, increasing teaching facilities for ophthalmic personnel, integration of ophthalmic care into the general health system and the promotion of blindness prevention in political organizations.