Related Experiment Video
Updated: Mar 13, 2026
Methods to Test Visual Attention Online
Published on: February 19, 2015
Real-Time Non-Intrusive Assessment of Viewing Distance during Computer Use
Marc Argilés1, Genís Cardona, Elisabet Pérez-Cabré
1*MSc †PhD Department of Optics and Optometry, School of Optics and Optometry of Terrassa (MA, GC, EP-C, JG), and Department of Automatic Control, Terrassa School of Engineering (RP-M, BM), Universitat Politècnica de Catalunya · BarcelonaTech, Terrassa, Spain.
Purpose:
To develop and test the sensitivity of an ultrasound-based sensor to assess the viewing distance of visual display terminals operators in real-time conditions.
Methods:
A modified ultrasound sensor was attached to a computer display to assess viewing distance in real time. Sensor functionality was tested on a sample of 20 healthy participants while they conducted four 10-minute randomly presented typical computer tasks (a match-three puzzle game, a video documentary, a task requiring participants to complete a series of sentences, and a predefined internet search).
Results:
The ultrasound sensor offered good measurement repeatability. Game, text completion, and web search tasks were conducted at shorter viewing distances (54.4 cm [95% CI 51.3-57.5 cm], 54.5 cm [95% CI 51.1-58.0 cm], and 54.5 cm [95% CI 51.4-57.7 cm], respectively) than the video task (62.3 cm [95% CI 58.9-65.7 cm]). Statistically significant differences were found between the video task and the other three tasks (all p < 0.05). Range of viewing distances (from 22 to 27 cm) was similar for all tasks (F = 0.996; p = 0.413).
Conclusions:
Real-time assessment of the viewing distance of computer users with a non-intrusive ultrasonic device disclosed a task-dependent pattern.
