Angioid streaks are often associated with a systemic condition, most frequently pseudoxanthoma elasticum, Paget's disease of the bone, or one of the sickle hemoglobinopathies. The clinical manifestations of angioid streaks and those three systemic conditions are reviewed. A diagnostic survey is suggested for patients discovered to have angioid streaks with no known systemic disease. The results of such a survey in 50 patients are presented. In addition, separate studies of patients with Paget's disease of the bone (50 patients) and of the sickle hemoglobinopathies (100 patients) are described, and the characteristics of patients with angioid streaks as well as the incidence of streaks in these conditions is reviewed. The histopathologic and fluorescein angiographic characteristics of angioid streaks, as well as the possible benefit of photocoagulation for complications of angioid streaks is discussed.