Disclosed herein is utilization of photosensor-oculography along with a video camera to implement a novel form of eye tracking, which can be important for many applications, such as augmented reality (AR) on smartglasses. In one embodiment, an eye tracking system includes a photosensor-oculography device (PSOG) that emits light and takes measurements of reflections of the light from an eye of a user, and a camera that captures images of the eye. A computer calculates values indicative of eye movement velocity (EMV) based on the measurements of the reflections obtained by the PSOG. These values then are used to determine how data is read from the camera, which can save power in some cases: the computer reads data from the camera at a higher bitrate when the values are indicative of the EMV are below a threshold compared to when the values are indicative of the EMV are above the threshold.