Several major follow-up studies are currently underway or are being planned to assess populations exposed to radiation from nuclear reactor accidents, contamination from nuclear weapons manufacturing, or fallout from nuclear testing. The data should help to define the true extent of the impact of environmental contamination; allow a better appreciation of the morbidity arising from such contamination; establish acceptable standards for ocular risk guidelines; develop a necessary database for retrospective dose reconstruction using cataract; and assess the contribution of environmental radiation exposure to the incidence of senile cataract development in general populations. Given the complexity of such studies, the potential confounders and the myriad possible methods of assessment, the global medical and scientific communities need to standardize methodologies and agree on minimum criteria to permit inter-study comparisons. Such standards have been developed in the present book, which presents a series of recommendations that represent the first codification of the manner in which studies should be executed. Minimum standardized criteria are given for the acquisition, archiving, evaluation and dissemination of data on the ocular risk of populations from environmental radiation exposure.