The invention is a device for examining the anterior and the posterior segments of the eyeball in a patient's eye, including a stereoscopic microscope system and an oscillating slit lamp disposed downstream of the stereoscopic microscope in the viewing direction in longitudinal direction to two parallel optical beam paths. The invention in the region between the binocular tube objective system and the main objective provides an optical deflection means which does not optically interfere with the stereoscopic beam paths of the stereoscopic microscope and via which an observation beam path and an illumination beam path of an ophthalmoscope can be coupled in in such a manner that the optical observation beam path and the illumination beam path deflected by the optical deflection means each pass through the main objective in viewing direction.