The EMGT is a collaborative effort that involves a Clinical Center at the Department of Ophthalmology of Malmo University Hospital at the University of Lund, Sweden, and its Satellite Center in Helsingborg, Sweden; an independent Data Center at the Department of Preventive Medicine, University Medical Center at Stony Brook, New York; and a Disc Photography Reading Center at the Department of Ophthalmology in Lund at the University of Lund. The study was initiated with support from the Swedish Medical Research Council.