A device for ophthalmologic, particularly refractive, laser surgery comprises a laser beam source (20) for emitting a focused treatment laser beam (200) and an optical coherence interferometric measuring apparatus (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 device. A processor (C) used as an evaluation and control unit is equipped to assess on the basis of the measured z-position as to whether a desired treatment location of the eye in the z-direction coincides with the focal plane of the treatment laser beam or is offset therefrom. Depending on whether or not the patient is correctly positioned with respect to the focal plane, the processor (C) can cause different reactions.
