A method and a device for detecting the spatial position of the optical axis of the eye of a human or animal subject and for centering a reference system in relation to the optical axis are described, having at least one light source emitting a parallel light beam bundle, a positioning region for the subject provided opposite the light source, means for relative position orientation of the parallel light beam bundle in relation to the eye of the subject, and at least one detector unit for detecting reflection events caused in and on the eye by the parallel light beam bundle. The present invention generates control signals on the basis of the scattering and reflection events detected by the detector unit, by which the means for relative position orientation are activated, the control signals being generated in such a way that at least one reflection event and at least one scattered light event are to be brought into congruency in relation to the propagation direction of the parallel light beam bundle.