If you are interested in eye tracking and HCI it's worth reading up on saccades (http://en.wikipedia.org/wiki/Saccade http://en.wikipedia.org/wiki/Saccade) and

If you are interested in eye tracking and HCI it's worth reading up on saccades (http://en.wikipedia.org/wiki/Saccade http://en.wikipedia.org/wiki/Saccade) and eye tracking (http://en.wikipedia.org/wiki/Eye_tracking http://en.wikipedia.org/wiki/Eye_tracking) I didn't do much HCI but worked with some HCI labs that did saccade analysis with photography and photo manipulation. Fascinating stuff.