As one technique of detecting an eye movement, there is electrooculography (EOG). In this technique, potentials of right eye and left eye (hereinafter referred as eye potentials) can be detected by attaching electrodes to the skin close to each of the right eye and the left eye. The eye movement can be detected based at least in part on a pattern of variation in the eye potentials.
Conventional eye movement detecting devices cannot detect a movement of the right eye and that of the left eye individually. Thus, it cannot distinguish whether the right eye and the left eye move in the same direction or in opposite directions.