We describe a method, based on recordings of the
electroencephalogram (EEG) and eye movement potentials
(electrooculogram), to track where on a screen (x,
y coordinates) an individual is fixating. The method
makes use of an empirically derived beam-forming filter (derived
from a sequence of calibrated eye movements) to isolate eye
motion from other electrophysiological and ambient electrical
signals. Electrophysiological researchers may find this method
a simple and inexpensive means of tracking eye movements and
a useful complement to scalp recordings in studies of cognitive
phenomena. The resolution is comparable to that of many commercial
systems; the method can be implemented with as few as four
electrodes around the eyes to complement the EEG electrodes
already in use. This method may also find some specialized
applications such as studying eye movements during sleep and
in human–machine interfaces that make use of gaze information.