Effect of Font Size and Glare on Computer Tasks in Young and Older Adults

Abstract

Productivity is improved when the font is increased from 1.78 or 2.23 to 3.56 mm for text-based computer tasks. The largest font size corresponds to a visual angle of font of 23.4 arcmin. This visual angle of font is above the high end of ISO recommendations (International Organization for Standardization, 1992, 2011). The findings may be useful for setting the font sizes for computers and for training office workers.

Viewing distance and eyestrain symptoms with prolonged viewing of smartphones

“…The perceived difficulty for a visual search task is greater when the font is smaller and subjective comfort ratings are reduced in the presence of visual stress associated with small fonts . The size of the font was held constant in this experiment, so it is not possible to draw any further conclusions about any relationship between font size, perceived difficulty and visual comfort.…”

“…Although subjects obeyed the instruction to sit with their body parallel to the camera, there was the risk of parallax errors, when calculating the viewing distance, if their alignment changed relative to the camera. Alternative methods for measuring this for further projects are to use an infrared sensor on the subject's head or a head‐mounted tool as described by Piccoli and colleagues …”

The pitfalls of the traditional office ergonomics model in the current mobile work environment: Is visual ergonomics health literacy the remedy?

“…There is also evidence that small size font can affect productivity, but this has only been demonstrated for desktop computer displays [22].…”

“…For example, Tegtmeier [5] describes how touchscreen and tablet users made postural adjustments and tilted their digital devices to avoid reflected glare on the device. Similarly, there are experimental studies which report that some users change their viewing distance in the presence of reflected glare on a computer display [22,28]. Ko and co-authors report in their experiments that reflective glare did not have a significant effect on productivity [22], but Shieh reports that subjective visual fatigue was rated as worse in the presence of reflections [28].…”

“…One way to mitigate the visual ergonomics health and performance problems associated with mobile work is to design equipment which facilitates comfortable and effective use. For example, set the default font size on digital devices to 3.6 mm because this has been shown to improve productivity, accuracy and ease with performing computer tasks [22] or include an adaptive feature on digital displays which automatically adjusts the luminance contrast between text and the background to assist reading comfort [49]. These types of engineering controls would remove or at least minimise the burden placed on workers to adjust their workstation and display for optimal comfort and use.…”