Work 51 (2015) 471–481 471 DOI 10.3233/WOR-141879 IOS Press Adjustable task lighting: Field study assesses the benefits in an office environment Sharon Joines a , Tamara James b,∗ , Siwen Liu a , Wenjiao Wang a , Rebecca Dunn b and Shane Cohen c a Industrial Design, College of Design, North Carolina State University, Raleigh, NC, USA b Ergonomics Division, Occupational & Environmental Safety, Duke University, Durham, NC, USA c Bosco Perry Design, LLC, Potomac, MD, USA Received 18 May 2013 Accepted 24 November 2013 Abstract. BACKGROUND: Lighting is a part of every work task in the office environment, yet it is often overlooked. Research links direct and indirect glare to increased risk of visual discomfort among office workers with symptoms ranging from dry eyes to blurry vision or headaches. Researchers have been primarily concerned with those characteristics of task lighting that cause glare including luminance level, position (line of sight), and control. It is unknown what the benefits of adjustable task lights are and whether or not their use has an effect on musculoskeletal comfort or posture. No comprehensive field evaluations of this type were found among peer-reviewed, indexed journals. OBJECTIVE: The purpose of this study was to assess the ergonomic and calculated utility power consumption benefits of adjustable LED task lighting in an office environment using a control/intervention experiment design. METHODS: One hundred participants were originally recruited and randomly assigned to intervention and control groups. Self-reported data was collected on level of eye fatigue, perception of job content, intervention usability, and musculoskeletal discomfort. Data was also collected on workspace level of illumination and posture during standardized tasks (assessed using RULA). RESULTS: Comparing baseline data to follow-up data for the intervention group, the use of the adjustable, LED task lights provided statistically significant, positive impacts on users’ rating of discomfort, eye fatigue, perception of job content, and posture between baseline and the short-term follow up. CONCLUSIONS: Significant benefits to musculoskeletal comfort, posture, and visual comfort were documented when partici- pants used the adjustable task lights. Participants’ assessments of the light’s usability, usefulness and desirability were positive. There were no negative results found with adjustable task light use. Keywords: Musculoskeletal, vision, usability, posture, discomfort 1. Introduction The impact of lighting on individuals while working has been investigated: luminance level significantly ef- fects task performance, comfort and productivity [1]; visual comfort, energy efficiency and performance [2]; * Corresponding author: Tamara James, Ergonomics Director, Duke University & Health System, Box 3834 DUMC, Durham, NC 27710, USA. Tel.: +1 919 681 3140; Fax: +1 919 286 6763; E-mail: tamara.james@duke.edu. line of sight impacted from produced glare (owing to fixed, cubicle shelf lights) for most females due to stature [3]; and posture during reading-writing tasks on the horizontal plane is effected by lighting param- eters [4]. A set of field simulation experiments in the US in 2006 [5] assessed effects of variations in light- ing quality on office worker performance, health, and well-being. They report the direct/indirect systems to be more comfortable than the direct-only systems, with a further increase in comfort associated with individ- ual control with no simple main effects of lighting 1051-9815/15/$35.00 c  2015 – IOS Press and the authors. All rights reserved