Abstract: An intra-operative medical image viewing system can allow a surgeon to maintain a viewing perspective on the patient while calling-up visual images on-the-fly. A digital image source has at least one image file representative of an anatomical or pathological feature of a patient. A display is worn by the surgeon or positioned between the surgeon and her patient during surgery. The display is selectively transparent, and exhibits to the surgeon an image derived from the image file. An image control unit retrieves the image file from the image source and controls the display so that at least a portion of the image depiction can be exhibited and modified at will by the surgeon. A plurality of peripheral devices are each configured to receive an image control input from the surgeon and, in response, generate an image control signal. Each peripheral accepts a different user-interface modality.