Walls et al. Respond

Abstract

Bierman and Rea outlined some corrections and offered further information regarding the lighting sources described in our article. We welcome their comments and respond to each point as follows. First and second, Bierman et al. stated that high-intensity discharge (HID) and fluorescent lamps of similar wattage are approximately equal in terms of efficiency and that light-emitting diode (LED) lamps appear far brighter than fluorescent lamps. Although we welcome such advice, it was beyond the scope of our study to determine the particular characteristics of HID or LED lamps required in a work environment using fluorescent lamps to produce the required concentration and visual acuity. Third, the description of the range of correlated color temperatures (CCTs) available in fluorescent lamps in the United States is interesting, but as Bierman et al. did not comment on them, we can only note their advice as being useful. In our article, we stated that exposure to fluorescent lighting in the workplace has increased and that such exposure is to lights of higher CCT—those more appropriate for commercial and industrial use. Fourth, their point relating to the flicker of fluorescent lamps is informative and useful. It would be desirable for this type of information to be better understood by lamp manufacturers and suppliers. Fifth, Bierman et al. suggested it to be misleading to characterize actinic effects in terms of CCT. As referenced in our article, however, there is considerable evidence in the literature suggesting harm from ultraviolet (UV) emissions from some light sources, based on a specific combination of CCT and wavelength. Sixth, there may be no scientific consensus that lamps of higher CCT improve concentration or mental activity level. However, several studies,1–3 including a recent prospective controlled intervention study conducted in a “real-world” workplace setting,4 strongly suggest this is the case. In our study, we provided a crude estimate of the likely number of additional cases of cataracts and pterygia annually in Australia caused by increased exposure to fluorescent lighting, based on reported prevalence and population-attributable fractions. As such, we illustrated the importance of considering the possible health impacts of new technologies implemented to mitigate the effects of climate change.