A microscope, comprising an observation beam path that renders an eye to be examined observable, a wavefront measuring device for measuring the refraction of the eye to be examined, an OCT device comprising an OCT illumination beam path, by means of which OCT illumination radiation can be focused as an OCT spot into the eye to be examined, and a control unit that is supplied with at least one measurement value of the wave front measuring device, is provided, wherein the control unit sets the beam diameter and/or the beam shape of the OCT spot on the basis of the at least one supplied measurement value.