A population-based series of retinal detachments (RD) collected during a 10-year period (538 patients, 590 'cases', i.e. diseased eyes including new RD after 6 months in the same eye) is reported. The annual incidence was 10.6 per 100,000 population. Bilaterality was observed in 11.2%. In this material preponderance of the right eye was found. In non-traumatic RD there was a small sex difference, with a higher incidence among females. Older persons were at high risk of sustaining RD, as were myopes. In myopic males the risk increased with the degree of myopia and with increasing age. In myopic females the greatest risk was found in the age group 30-59 years. Myopic eyes are probably also more vulnerable to traumatic RD. Lattice degeneration was more common in middle-aged than in older patients and was also more common in myopic eyes than in eyes with other phakic RD. High myopia (greater than -5D) was more frequent in patients with lattice degeneration than in those without. Aphakia was found to be an important predisposing factor for RD. A classification taking into account the above-mentioned factors is proposed.