1. A computer implemented method for segmenting a video stream, comprising: determining an approximate location of an eye within a video stream comprising a set of images to identify an area of interest within one or more images of the set of images; binarizing the area of interest within the one or more images to generate a binarized image from the video stream; identifying an initial pupil location of a pupil of the eye within the binarized image; determining an initial iris radius for the eye by identifying, within the binarized image, a first distance from a first corner of the eye to an outer edge of the iris and a second distance from a second corner of the eye to the outer edge of the iris and determining the initial iris radius based on the first distance and the second distance; and determining a final pupil location and a final iris radius based at least in part on the initial pupil location and the initial iris radius.