A Fitts' Law Study of Click and Dwell Interaction by Gaze, Head and Mouse with a Head-Mounted Display

Gaze and head tracking, or pointing, in head-mounted displays enables new input modalities for point-select tasks. We conducted a Fitts' law experiment with 41 subjects comparing head pointing and gaze pointing using a 300 ms dwell (n = 22) or click (n = 19) activation, with mouse input providing a baseline for both conditions. Gaze and head pointing were equally fast but slower than the mouse; dwell activation was faster than click activation. Throughput was highest for the mouse (3.24 bits/s), followed by head pointing (2.47 bits/s) and gaze pointing (2.13 bits/s). Dwell activation was faster than click activation. The effective target width for gaze(approximate to 94 pixels; about 3 degrees) was larger than for head and mouse (approximate to 72 pixels; about 2.5 degrees). Subjective feedback rated the physical workload less for gaze pointing than head pointing.