A method to furnish input representing gaze direction in a computer system operatively coupled to a vision system. In this method, a first image of an eye at a first level of illumination is acquired by a camera of the vision system. The first image is obtained from the camera, and a second image of the eye corresponding to a second, different level of illumination is also obtained. Brightness of corresponding pixels of the first and second images is compared in order to distinguish a reflection of the illumination by the eye from a reflection of the illumination by eyewear. The input is then furnished based on the reflection of the illumination by the eye.