A comprehensive review of all ocular surveys (40) of leprosy patients was undertaken. These surveys do not provide adequate information for defining the incidence or prevalence of ocular disease caused by Mycobacterium leprae. Furthermore, the level of disability and blindness from leprosy has not been addressed. The primary methodologic problems in these surveys are: a) lack of survey sampling techniques, b) institution-based or. clinic-based populations as the study population, c) inadequate instruments for the detection of clinical signs, d) non-ophthalmically trained individuals as examiners, e) definition of "ocular" disease that includes non-ocular conditions, f) failure to analyze by disease type, and g) failure to analyze by duration of disease or therapy. All of these studies were cross-sectional in nature. While this type of study is beneficial to health administrators for prioritizing eye care in health planning, a longitudinal study is required to investigate the risk factors for ocular involvement and blindness in these patients.