Abstract: The image-based system is used to observe and document eye responses, which include eye gaze tracking, pupil size and reactivity, for either one or both eyes sequentially or simultaneously as well as eye lid movements, condition of the sclera, etc. that are recorded and evaluated by police officers. The system includes a faceplate against which the subject places their face. The faceplate can have illumination devices mounted thereon which transmit beams of infrared light and visual light to illuminate the subject's eyes. An imaging device is removably mounted on the frame of the image-based system to observe and document eye responses to generate images of the subject's illuminated eyes. The generated images are also transmitted to an image display device for display to a test administrator.