WHERE SHALL I PUT MY VDT

Title WHERE SHALL I PUT MY VDT
Author, Co-Author Peter Howarth
Topic
Year
1994
Day
Monday
Program Number
2:00 pm
Room
San Diego Ballroom A
Affiliation
Abstract In order to prescribe appropriate spectacles for computer users we need to know where people wish to have their screens positioned. The present study examines this question. The main problem with previous studies which measured working distances employed by VDU users is that we do not know whether these distances were chosen by the user, or were enforced upon them. This enforcement could have happened because of the physical constraints of the workplace, because of the limitations of the user's spectacle prescription, or even just because the person was unaware of the adjustability of their equipment. Fifteen young subjects, who were unaware of the true nature of the experiment, adjusted the position of a screen whilst performing a character-recognition task. Three different size screens were used, 12, 14 and 17 inches, with five font sizes ranging from 2mm to 6mm displayed on each. For each trial, subjects were filmed for 40 seconds using a hidden video camera. The distances from the eye to the screen were subsequently measured from the recording every 10 seconds and averaged over the trial. Viewing distance ranged from 27.6 to 78.4 cm. with an overall mean distance of 53.2 cm. (s.d. 10.8). Text size affected the viewing distance only slightly - there was an increase in average viewing distance from 49.6cm for the 2mm text to 55.3 cm for the 6mm text, and monitor size did not affect the viewing distance chosen. Although there were large between-subject differences, each individual subject varied little in chosen viewing distance for the different screen and font sizes. Visual performance (measured as errors in character recognition) decreased as font size was reduced, and surprisingly subjects did not sufficiently change their viewing distance to compensate for this decrement. We conclude that the subjects wished to have their screens at a distance that was idiosyncratic to themselves, irrespective of the size of the monitor or the visual task.
Affiliation of Co-Authors
Outline