A surgical microscope assembly includes a microscope main objective and microscope imaging optics. The microscope main objective and microscope imaging optics define a viewing beam path that passes from a sample through the microscope main objective and the microscope imaging optics. The assembly includes an optical coherence tomography (OCT) unit having an illumination beam and a collection beam and a beamsplitter between the microscope main objective and the microscope imaging optics. The beamsplitter is configured to direct a portion of light from the microscope main objective to the microscope imaging optics and to direct another portion of light from the microscope main objective to the OCT unit collection beam. The beamsplitter is further configured to direct an illumination beam from the OCT unit to the microscope main objective and to the sample. A beam forming unit is between the OCT unit and the beamsplitter. The beam forming unit is configured to form the illumination beam of the OCT unit so as to generally correspond to a size of the microscope main objective.