56 C.T. Guo et al.
no significant reduction in variance of eye motion was found. This indicated that
even with an eye fixation pointer placed at the centre of the screen and with instruc-
tions to fixate ones’ eyes, it was difficult to fixate ones’eyes while actively playing
the game.
For Experiment two, eye fixation significantly reduced eye motion in both hori-
zontal and vertical directions. A Matlab program was run to identify duration of
stop (<= 2 dps), smooth pursuit (<=40 dps and >2dps) and saccadic eye motion
(>40 dps). On average, 62% of the time, eye motion was categorized as “stop”,
37% of the time categorized as “smooth pursuit” and no more than 1% of the
time categorized to “saccadic”. There was no significant correlation between these ...