The Coordinating Office for Radial Keratotomy (CORK) will provide the Prospective Evaluation for Radial Keratotomy (PERK) project with (1) assistance in maintaining high quality data collection, and in obtaining maximal follow up, and (2) comprehensive database management and statistical services. Three phases of activity for the Coordinating Office are (1) planning (3-6 months), (2) accession and early follow up, and (3) late follow up. In the planning phase, the Coordinating Center will collaborate with PERK on forms design, and development of group procedures for data collection, and will implement these procedures. In the accession and early follow up phase, CORK will collect and computerize all data forms, implemenet procedures to closely monitor participant follow up, and produce interim reports. In the late follow up phase, the Coordinating Office will continue data collection activities, and produce reports and analyses of results. These duties will be discharged by five personnel: a statistician (PI), a statistical programmer, a data coordinator, a data entry operator, and a secretary.