From P2P Foundation

= an open source application that uses an ordinary webcam to estimate the direction of your gaze

URL = http://www.inference.phy.cam.ac.uk/opengazer

Description

"'Opengazer is an open source application that uses an ordinary webcam to estimate the direction of your gaze. This information can then be passed to other applications. For example, used in conjunction with Dasher, opengazer allows you to write with your eyes. Opengazer aims to be a low-cost software alternative to commercial hardware-based eye trackers."