1. An optical marker for use in a motion tracking system for tracking motion of a subject to which the optical marker is coupled, the optical marker comprising: two or more targets, each of the two or more targets comprising a front surface and a back surface, wherein the front surface comprises one or more artwork, wherein the one or more artwork is configured to be detected by one or more detectors of the motion tracking system, wherein the one or more artwork comprises one or more landmarks configured to be viewable in an image of the optical marker, wherein at least one of the two or more targets is adapted to be placed on one side of a nose of the subject, and wherein at least another one of the two or more targets is adapted to be placed on another side of the nose of the subject; and a substrate coupled to the back surface, wherein the substrate is adapted to be removably attached to a nose bridge of the subject as to substantially prevent movement of the substrate with respect to head movement of the subject.