  A custom head-mounted system to track smooth eye movements for control of a
mouse cursor is implemented and evaluated. The system comprises a head-mounted
infrared camera, an infrared light source, and a computer. Software-based image
processing techniques, implemented in Microsoft Visual Studio, OpenCV, and
Pupil, detect the pupil position and direction of pupil movement in near
real-time. The identified direction is used to determine the desired
positioning of the cursor, and the cursor moves towards the target. Two users
participated in three tests to quantify the differences between incremental
tracking of smooth eye movement resulting from the Vestibulo-ocular Reflex
versus step-change tracking of saccadic eye movement. Tracking smooth eye
movements was four times more accurate than tracking saccadic eye movements,
with an average position resolution of 0.80 cm away from the target. In
contrast, tracking saccadic eye movements was measured with an average position
resolution of 3.21 cm. Using the incremental tracking of smooth eye movements,
the user was able to place the cursor within a target as small as a 9 x 9 pixel
square 90 % of the time. However, when using the step change tracking of
saccadic eye movements, the user was unable to position the cursor within the 9
x 9 pixel target. The average time for the incremental tracking of smooth eye
movements to track a target was 6.45 s, whereas for the step change tracking of
saccadic eye movements, it was 2.61 s.

Human-Computer Interaction