The importance of including position and viewing direction when measuring and assessing the lighting conditions of office workers.

This paper measures office lighting conditions and worker viewing behaviour; it does not provide clinical evidence that lighting changes alertness, health, or performance. The observational study had only six workers, all at one university, observed for one workday, and they were selected by workstation location rather than randomly. The workers were observed without prior notification or ethical approval, although the authors state this complied with Dutch law and the data were untraceable. The sample calculation assumed eight hours at the workstation and a minimum vertical illuminance of 500 lx, so the 4.6% exposure difference depends on those assumptions. The experiments used controlled rooms, including one artificial-window setup and one real-daylight setup with only one configuration, so the multiplication factors may not apply to every office. The literature review searched only four combinations of terms and included 26 papers, so it may not capture all relevant light and alertness studies. The authors note that job type, workstation setup, monitor settings, task lighting, sit-stand use, office layout, and eye function can change where workers look.

The authors declared no conflicts of interest. The supplied text does not report a funding source.

Do not conclude that facing a window makes office workers more alert, healthier, or more productive. The reported experiments measured light levels and viewing directions, not alertness or health outcomes.