Abstract: A drape for a surgical microscope comprising a flexible cover for separating the microscope from the surgical field. There is a frame in the cover adapted to be secured over the objective lens of the microscope, and a dome-shaped protective window in the frame. The window is oriented so that when the frame is secured over the objective lens the dome extends toward or away from the objective lens to minimize reflection of light from the protective window into the optical path of the microscope.

Abstract: A zonal beamsplitter for use with surgical microscopes including a pair of right triangular prisms positioned adjacent to each other in opposing relation along substantially planar surfaces defining their respective hypotenuses. The planar surface of one prism is bi-zonal and includes a first zone for diverting substantially all of a portion of an image-quality optical signal at an angle from the direction of travel of the optical signal, and a second zone for conducting substantially all of the remaining image-quality optical signal therethrough. The plane of the first zone may be offset from that of the second zone and/or coated with an opaque reflective surface such as a metal foil.