Please cite this work as: Hamedani, Z., Solgi, E., Skates, H., Hine, T., & Isoardi, G. (2018). Physiological Responses In Relation To Glare: A Case Study In Office Setting. In CIE Expert Tutorial and Workshops on Research Methods for Human Factors in Lighting, August 13-14, Copenhagen, Denmark.
PHYSIOLOGICAL RESPONSES IN RELATION TO GLARE: A CASE STUDY IN OFFICE SETTING 1
1st Hamedani, Z.1, 2nd Solgi, E1, 3rd Skates, H1, 4th Hine, T1, 5th Isoardi, G2 Griffith University, Gold Coast, AUSTRALIA, 2 QUEENSLAND UNIVERSITY OF TECHNOLOGY, Brisbane, AUSTRALIA [email protected]
Abstract The modern work setting is tailored to productivity, health, satisfaction, and comfort. A recognized factor that reduces productivity in workplaces is discomfort glare. While the perception of objects may not necessarily be impeded, discomfort glare affects the observer with experiences of discomfort, fatigue, and headaches. So far, we know that the main human responses to discomfort glare are psychological and subjective negative responses. Therefore, quantification of discomfort glare proves to be a challenging task. In quantifying the perceived glare, the existing models for glare analysis are driven by photometric measurements in the user field-of-view and subjective evaluation. Measuring visual discomfort through subjective and self-reported evaluations that prevail, has been widely criticized for the intrinsic uncertainty of these methods, the de Boer glare category rating scale an example. The visual discomfort reported by participants can be attributed to luminance distribution and a wide range of factors including but not limited to user background or biological differences. Consideration of biological reactions and ocular behaviour, may permit a parallel objective means of determining discomfort glare and reducing the uncertainties about category rating scale assessment. Several studies have already addressed light induced ocular behaviour such as pupil dilation and degree of eye-opening in different lighting conditions. Research to date has not yet determined whether, and to what extent, objective measures of human ocular reactions and light-induced gaze behaviour are affected by glare in a working environment. In this research, an experimental study was performed to investigate these factors in detail. The experiment was carried out on the Gold Coast, Australia, in a cellular office with north-west orientation and a high proportion of glazing. In this experiment, four lighting conditions with different discomfort glare levels and light distribution were determined as independent variables. Participants were asked to perform different types of office visual tasks while their eye and gaze related data were recorded in conjunction with photometric measurements. A lightweight eye-tracking device was used to provide gaze and ocular behaviour data that was subsequently incorporated into a visual performance analysis. High Dynamic Range (HDR) imaging was used, as a luminance mapping technique, to record the luminance distribution in a room and also provide input to existing glare models. To provide a better understanding of user ocular behaviour, a subjective evaluation of user sensitivity to glare using the Conlon method (which is a two-parameter Rasch Rating Scale model) was performed prior to commencing the experiment. The results indicate that the pupillary oscillation and the number of blinks when participants are exposed to glare was more significant in later phases of the task. It was also found that the magnitude of fluctuation in photopupillary reflexes is task dependent. Moreover, in the same lighting condition, the user sensitivity to glare highly justifies the different physiological responses and reported glare by users. Discrepancies exist between predictive models and user perception. In order to provide a predictive model that more realistically acknowledges issues of human subjectivity and behaviour, it is beneficial to add more quantitative measurements in conjunction with predominant glare research method (using subjective evaluation and luminance mapping) which are involuntary and independent of judgement and bias. In the next step of this study, physiological responses along with visual performance will be examined.