Visual effects of the luminance surrounding a computer display

Abstract

The luminance surrounding a computer display can potentially reduce visibility of the display (disability glare), result in sensations of discomfort (discomfort glare) and result in transient adaptation effects from fixating back and forth between the two luminance levels. The study objective was to measure the effects of surround luminance levels upon these functions in younger and older adults to determine recommended surround luminance levels. The younger age group comprised 20 subjects (mean age 27.9 years, range 23 - 39) and the older group 17 subjects (mean age 55.5 years, range 47 - 63). The central task was presented with luminance of 91 cd/M(2), tested surround luminance levels were 1.4, 2.4, 8.9, 25.5, 50, 91, 175, 317, and 600 cd/M(2). Disability glare was tested with low contrast (20%) visual acuity charts, transient adaptation was tested with a task that required regular fixation between the two luminance levels, discomfort was measured with a questionnaire after reading stories with different surround luminance levels, and preferred luminance was measured by method of adjustment. The surround luminance significantly affected transient adaptation (p < 0.0001), optimal performance occurred at 50 cd/M(2) and above for the young group and at 91 cd/M(2) and above for the older group. Neither low contrast acuity (disability glare) nor symptoms when reading were significantly affected by surround luminance. There was wide variation in preferred surround luminance; however, average preferred surround luminance was 86.9 cd/M(2) for the young group and 62.2 cd/M(2) for the older group, slightly below the central luminance of 91 cd/M(2). The effects of the surround luminance within the tested range are not large; however, the data show that the lowest surround luminance levels should be avoided and that surround luminance levels at or slightly below that of the central task are preferred.

Subjective responses to display bezel characteristics

“…This is exactly the same situation as is found with tablets, such as the ipad and the Google Nexus 7, where a search of the internet reveals that opinions on the colours and glossiness of the surrounds is divided -and presumably the market forces will prevail. Our findings, along with our previous findings (Howarth and Hodder, 2004) and those of Soderston et al 2003, Hunter et al, 2003, Sheedy et al 2005and Hisatake et al 2011 all indicate that there is no need for standards organizations to impose limits on either the glossiness or the colour of display bezels. …”

“…Other studies to date [Soderston et al 2003, Hunter, Boyce and Watt, 2003, Howarth and Hodder, 2004, Sheedy et al 2005, Hisatake et al 2011] present the opposite view and indicate that the bezel characteristics do not affect either performance or comfort. However, these studies can all be criticised (as can that of Belánd and Andrén, 2008) on the grounds that they were laboratory studies of restricted time and scope, and did not examine the effect of bezel colour or gloss during normal work.…”

Computer Display Placement for Progressive Addition Lens Wearers: A Field Observation of Multiple Display Conditions

“…The survey for eye discomfort utilized descriptors used by Sheedy et al (2005) on a 10-point response scale. The survey for body discomfort was modeled after the survey used by Amick et al (2003), and also incorporated a 10-point response scale.…”

Effect of illumination, noise and text/background colour on spontaneous eye blink rate

“…Previous studies showed that illumination in a VDT workplace was a significant parameter affecting visual performance and visual fatigue , Chen and Lin 2004, Sheedy et al 2005. Lin et al (2009) showed a significant effect of ambient illumination in a searching task.…”