Longitudinal evaluation of discrete consecutive gaze gestures for text entry

Eye-typing performance results are reported from controlled studies comparing an on-screen keyboard and Eye Write, a new on-screen gestural input alternative. Results from the first pilot study suggest the presence of a learning curve that novice users must overcome in order to gain proficiency in EyeWrite's use (requiring practice with its letter-like gestural alphabet). Results from the second longitudinal study indicate that EyeWrite's inherent multi-saccade handicap (4.52 saccades per character, frequency-weighted average) is sufficient for the on-screen keyboard to edge out Eye Write in speed performance. Eye-typing speeds with Eye Write approach 5 wpm on average (8 wpm attainable by proficient users), whereas keyboard users achieve about 7 wpm on average (in line with previous results). However, Eye Write users leave significantly fewer uncorrected errors in the final text, with no significant difference in the number of errors corrected during entry, indicating a speed-accuracy trade-off. Subjective results indicate that participants consider Eye Write significantly faster, easier to use, and prone to cause less ocular fatigue than the on-screen keyboard. In addition, Eye-Write consumes much less screen real-estate than an on-screen keyboard, giving it practical advantages for eye-based text entry.