Abstract: In order to determine the focus position of a laser beam (60, 60a) in an ophthalmological laser projection system (1), at least one measurement marking (3) applied to a reference area (20) is passed over by means of the laser beam (60, 60a) along a scanning path. A measurement signal created by passing over the measurement marking (3) is captured. Time values from at least one signal edge created in the measurement signal when passing over edges of the measurement marking (3) are determined and the focus position is established on the basis of the time values. By scanning defined measurement markings (3) and establishing time values of signal edges created when edges of the measurement marking (3) are passed over, it is possible to determine the focus position of the laser beam (60, 60a) without focusing movements being required for this during the measurement.