The Leica HM500 head-mounted surgical microscope combines the flexible properties of the human eye with the magnification capabilities of loupes and surgical microscopes. The device is worn comfortably and provides continuously variable magnification, automatic parallax correction and sharp 3D images for precise viewing during surgery. This high precision optical system features an optical zoom that allows a variable selection of magnification between 2X and 9X, depending on the particular eyepieces in use. Highly responsive autofocus sensors detect a specific object in the surgical field and adjust the optics as quickly and inconspicuously as the human eye to ensure a clear 3D image at every working distance. The optical zoom, focus,and autofocus are controlled by a rechargeable, battery-operated foot pedal, which provides convenience and flexibility in the operating room.