Effects of lensed-indirect and parabolic lighting on the satisfaction, visual health, and productivity of office workers.

A pre- and post-renovation survey evaluated the reactions of office workers to two office lighting systems: a parabolic downlighting system and a ceiling suspended, lensed-indirect uplighting system. Questionnaire data on work content, perception of ambient environmental conditions (including office lighting), work-related health symptoms, job stress, job satisfaction, and self-reported productivity, and environmental data on illumination, air temperature, and relative humidity were collected. The lensed-indirect lighting system was more favourably rated on several subjective lighting impressions scales, and for computer work workers reported fewer screen glare problems, and fewer and less frequent problems with tired eyes and eye focusing. Productivity was less hindered by the lensed-indirect lighting, and satisfaction with office lighting and ratings of lighting quality were significantly higher for this system. These reactions were not associated with any differences in levels of illumination between the lighting systems. Ratings of lighting satisfaction and lighting importance were inversely related. Overall, some two-thirds of workers indicated a preference for working under the lensed-indirect lighting system.