Techniques for eye-tracking in a near-eye display system are disclosed. One example of a near-eye display system includes a waveguide-based display substrate that is transparent to visible light and configured to be placed in front of a user's eye. The waveguide-based display substrate includes a first surface area configured to specularly reflect a first portion of invisible light reflected by the user's eye to a camera to form a first image of the user's eye in a first area of an image frame, and a light deflector embedded in the waveguide-based display substrate or formed on a second surface area of the waveguide-based display substrate. The light deflector is configured to direct a second portion of the invisible light reflected by the user's eye to the camera to form a second image of the user's eye in a second area of the image frame.