1. A system for determining gaze-tracking locations, comprising: a device configured to be worn on a wearer's head; one or more illumination sources mounted on the device within a field of view of an eye of a wearer wearing the device and oriented to illuminate the eye, the one or more illumination sources configured to minimize interference with the wearer's vision within the field of view; an eye-tracking camera mounted on the device and positioned for viewing the eye; and a processor coupled to the eye-tracking camera for analyzing images of the eye acquired by the eye-tracking camera to identify one or more glints reflected off the eye from the one or more illumination sources and identify the location of features of the eye relative to the one or more glints to determine locations being viewed by the wearer; further comprising one or more additional eye-tracking cameras mounted on the device and positioned for viewing the eye, the processor coupled to the one or more additional eye-tracking cameras to track locations of the eye from different viewing angles, wherein the eye-tracking cameras are sufficiently spaced apart from one another such that the features of the eye appear in eye-tracking camera images from at least one of the eye-tracking cameras when the eye moves through its complete normal range of motion.