The Collaborative Ocular Melanoma Study (COMS) is a set of randomized clinical trials sponsored by the National Eye Institute of the National Institutes of Health. The COMS is being conducted to evaluate the role of radiotherapy in the treatment of patients with choroidal melanoma. Primary choroidal melanoma can enlarge or metastasize and eventually cause death in a significant percentage of cases. The primary COMS trial is designed to determine whether enucleation (removal of the eye) or radiotherapy without removal of the eye provides the patient with the longest remaining lifespan. More than 40 clinical centers in the United States and Canada are participating in the COMS. The objective of the COMS is to assess the effect of treatment upon 5-year and 10-year survival and the reduction or elimination of the disease process in patients randomly assigned to receive either radiation or enucleation. An ancillary component of the COMS, referred to as the COMS-QOLS, was designed to measure the impact of disease and its treatment on quality of life. The two treatment approaches being investigated, enucleation and radiation therapy, are likely to have different psychological and physiological effects on the patients receiving them. The COMS-QOLS assessments include the SF-36 Health Survey, the Activities of Daily Vision Scale (ADVS), the Visual Functioning Questionnaire (VFQ), and the Hospital Anxiety and Depression Scale (HADS). Patients are interviewed at selected intervals during follow-up; in addition, 200 patients will be interviewed before randomization and have repeat interviews at six months and annually after randomization. The patient's quality of life after treatment will become an important consideration in determining the best form of therapy, particularly in the event that no survival difference between treatment groups is found.