We present a system locating the contour of an iris in space using robust active ellipse search and correspondenceless stereo. Robust iris location is the basis for gaze estimation and tracking, and, as such, an essential module for augmented and virtual reality environments, The system implements a robust active ellipse search based on a multi-scale contour detection model. The search is carried out by a simulated annealing algorithm, guaranteeing excellent performance in spite of heavy occlusions due to blinking, uncontrolled lighting, erratic target motion, and reflections of unpredictable scene elements. Stereo correspondence is avoided altogether by intersecting conjugate epipolar lines with the located ellipses. Experiments on synthetic and real images indicate very good performance of both location and reconstruction modules. © Springer-Verlag Berlin Heidelberg 2006.