Trachomatous low vision can be prevented by treating or preventing infection or through surgery to treat trichiasis. Resource allocation to prevent trachomatous low vision should be directed to those interventions that are the most cost-effective. In order to assess which of many potential interventions are the more cost-effective, data on the epidemiology of the disease, the effectiveness of community- and facility-based interventions, and the cost of the interventions are required. This paper provides a stylized model of the path from risk of infection through disease to trachomatous low vision or blindness that delineates the points at which interventions may occur and for which data are required. The literature reveals a considerable amount of data regarding the epidemiology of the trachoma and its sequelae but little on the effectiveness of community-based interventions and only one study that measured costs directly. More data are needed to assist policy makers and international program partners who seek to make efficient resource allocation decisions in an effort to eliminate trachoma as a cause of incident blindness in the developing countries in which trachomatous blindness remains prevalent.