Current surgical microscope systems have excellent optical properties but still involve some limitations. A future fully digital surgical microscope may overcome some major limitations of typical optomechanical systems, like ergonomic restrictions or limited number of observers. Furthermore, it can leverage and provide the full potential of digital reality. To achieve this, the frontend, the reconstruction of the digital twin of the surgical scenery, as well as the backend, the 3-D visualization interface for the surgeon, need to work in real-time. To investigate the visualization chain, we developed a virtual reality environment allowing pretesting this new form of 3-D data presentation. In this study, we wanted to answer the following question: How must the visualization pipeline look like to achieve a real-time update of the 3-D digital reality scenery. With our current approach, we were able to obtain visualizations with a frame rate of 120 frames per second and a 3-D data update rate of approximately 90 datasets per second. In a further step, a first prototype of a real-time mixed-reality head mounted visualization system could be manufactured based on the knowledge gained during the virtual reality pretesting.