1. A method of operating a see-through display system, the see-through display system comprising a see-through display screen, a gaze detection subsystem comprising an inward facing image sensor configured to acquire image data of each eye of a user of the see-through display system, and an outward facing image sensor configured to acquire images of a background scene relative to the user, the method comprising: acquiring an image of an external display screen located in the background scene and viewable through the see-through display screen via the outward facing image sensor; acquiring one or more images of each eye of the user via the inward facing image sensor; determining via the one or more images of each eye of the user and the image of the external display screen a location on the external display screen at which the user is gazing through the see-through display screen; obtaining an identity of an object displayed on the external display screen at the location determined; and performing an action based upon the identity of the object.