An apparatus for ophthalmological, in particular refractive, laser surgery includes a laser-beam source (20) for emitting a focused treatment laser beam (20′) and also includes an optical-coherence interferometric measuring device (34), for example an OLCR pachymeter, for measuring the z-position of a predetermined point of an eye to be treated in the coordinate system of the laser-surgery apparatus. A computer (C) serving as evaluating and control unit has been set up to assess, on the basis of the measured z-position, whether a desired treatment point of the eye in the z-direction falls in the focal plane of the treatment laser beam or is offset in relation to said plane. Depending on whether or not the patient is correctly positioned in relation to the focal plane, the computer (C) can bring about a range of actions.