An apparatus for ophthalmic laser surgery includes a contact surface for shaping abutment of an eye to be treated, a first radiation-source for making a treatment laser beam available, optical components for directing the treatment laser beam through the contact surface onto the eye and also a measuring device for measuring at least one corneal thickness dimension or/and positional dimension of the eye bearing against the contact surface, whereby the measuring device makes measured data available that are representative of the measured at least one thickness dimension or/and positional dimension. The measuring device preferably serves for positional surveying of the corneal posterior surface of the eye, whereby an electronic evaluating and control arrangement connected to the measuring device brings about a focus control of the treatment laser beam in a manner depending on the measured position of the posterior surface of the cornea.
