Environmental factors need to be considered as well. In general, people need different levels of luminance or brightness to read printed text than to read VDU text. Because VDUs are self-illuminating, VDUs are more comfortably used with a lower lighting level. If work involves a mix of VDU and other work then task lighting may assist. Other environmental factors such as thermal comfort can effect visual comfort, eg.
Lighting is also a factor in the 'star' configuration of workstations.