Visual ergonomics of video-display-terminal workstations: Field measurements of luminance for various display settings Francesco Leccese, Giacomo Salvadori, Michele Rocca ⇑ Department of Energy Engineering, Systems, Territory and Constructions (DESTeC) – Lighting and Acoustic Laboratory, School of Engineering, University of Pisa, Largo Lucio Lazzarino, Pisa, Italy article info Article history: Received 16 November 2015 Received in revised form 5 February 2016 Accepted 11 February 2016 Available online 15 February 2016 Keywords: Requirements for electronic visual displays Field assessment of display luminance Display luminance Luminance ratio Contrast non uniformity abstract Electronic visual displays have shown a rapid technological evolution in the last two decades. With ref- erence to the ergonomic requirements for video display terminal (VDT) workstations (ISO 9241), at an international level, attention is focused on the human–system interaction. With reference to visual ergo- nomics, the aim of this study is to assess luminance conditions through in-field measurements in order to evaluate: luminance and contrast ratios, luminance and contrast non-uniformities. The assessment was applied to widespread flat screen displays and repeated for fourteen combinations of Contrast– Brightness. The analysis carried out by the Authors shows the importance of realizing a simple and quick procedure to determine the performance levels of displays used in VDT workstations. The proposed assessment could be used as a practical tool for staff assigned to assess the risks arising from VDT use in the workplace within the Occupational Health and Safety Assessment Procedure. Ó 2016 Elsevier B.V. All rights reserved. 1. Introduction The introduction of computers has led to dramatic changes in work practices for many people. Today, activities such as reading, writing, and typing can be carried out without moving from a com- puter. This change in work practices has been accompanied by an increase in complaints about a number of health problems associ- ated with working at video display terminals (VDT) [1]. Eye dis- comforts and also hand/wrist problems are often associated with VDT work. Results of different studies suggest that VDT users have increased the risk of developing eye discomforts, musculoskeletal pains and mental load [2–7]. As the work force becomes more and more dependent on computers, the need for proper and effi- cient design of VDT workstations [8] and also the need for risk assessment procedures [9] become increasingly critical. With special reference to visual ergonomics, the main device of the VDT workstation is the monitor, because it represents the pri- mary object of vision. The task of the monitor is to reproduce infor- mation; the quality of the information reproduced can sometimes be crucial for properly carrying out work tasks, especially if partic- ular workstations are considered such as those used in mission critical control rooms (i.e. control rooms in airports, police stations, civil protection units,...). As a visual object, a monitor is substantially different from a sheet of paper in many ways and viewing a monitor is much more visually demanding than viewing paper [10]. Unlike paper, a self- illuminated monitor, which is refreshed at a certain rate, and con- sists of different combinations of background and foreground caus- ing different contrasting color objects that influence visual fatigue and can contribute to the outbreak of the Computer Vision Syn- drome [11–14]. The objects displayed on a monitor consist of a ser- ies of pixel-based dots with decreasing brightness on their outer edges, thus making it hard for the eyes to focus. In addition, the viewing distance between the eyes and the computer screen is important and often not easily adjusted, especially if compared with the simple movement of a book to adjust viewing distance [12,14–18]. Monitors have undergone a rapid technological development and over the past 20–30 years we have gone from CRT phosphor monochrome displays to CRT color displays and then from LCD dis- plays to the current LED displays. This evolution has resulted in an increase in the resolution and consequently in an improvement of visual performance and visual comfort as demonstrated by Ziefle [19]. Although displays realized with these new technologies can be considered photobiological risk exempt, as demonstrated by the extensive studies on the equipments commonly used in office workplaces [20–24], their effects on visual fatigue are still under investigation. To obtain good visual performance while working at a VDT it is very important that luminance contrast and screen luminance are http://dx.doi.org/10.1016/j.displa.2016.02.001 0141-9382/Ó 2016 Elsevier B.V. All rights reserved. ⇑ Corresponding author at: Largo Lucio Lazzarino, 56123 Pisa, Italy. E-mail address: michele.rocca.au@gmail.com (M. Rocca). Displays 42 (2016) 9–18 Contents lists available at ScienceDirect Displays journal homepage: www.elsevier.com/locate/displa