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The eye tracking device is shown at the left hand side. Aside are images from the eye tracker video, showing from left to right the gaze to the monitor, to the keyboard and to a paper.
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1. Introduction This paper gives an overview of our ongoing research in the field of non-specific effects of light, also called photobiological effects, on humans. At the conference "Licht 2002" in Maastricht, a need for additional data on the spatial, spectral and time integration of radiation by the visual system was identified (Schierz, 2002). T...
Citations
... Lin et al., 2015;Vincent, Baddeley, Correani, Troscianko, & Leonards, 2009). These studies deny the fixed assumption of gaze direction (gd) (Hubalek & Schierz, 2004) and recommend balance luminance distribution in FOV to avoid transient adaptation when working on different tasks (Kokoschka and Haubner 1985). Dependencies on visual context such as task or view outside have also been shown in several studies (Hamedani et al., 2019). ...
... A few studies have investigated the relationship between gaze shifts and building-induced visual context such as windows [56] or compositional effects of light [49], [53], [57]. These studies deny the fixed assumption of gaze direction, suggesting that gaze rests on vertical and horizontal planes and is not fixed exclusively on the task area [58]. While certain luminance ratios in the field-of-view have been recommended to avoid constant visual re-adaptation for better visual performance [49], extending gaze direction to an angular adaptive zone is also suggested [10]. ...
This paper introduces a novel approach for the assessment of daylight performance in buildings, venturing beyond existing methods that evaluate 2-dimensional illumination and comfort within a fixed field-of-view in order to predict human responses to light concerning non-visual health potential, visual interest, and gaze behavior in a visually immersive scene. Using a 3D rendered indoor environment to exemplify this coordinated approach, the authors assess an architectural space across a range of view directions to predict non-visual health potential, perceptual visual interest, and gaze behavior at the eye level of an occupant across an immersive field-of-view. This method allows the authors to explore and demonstrate the impact of space, time, and sky condition on three novel daylight performance models developed to predict the effects of ocular light exposure using a human-centric approach. Results for each model will be presented in parallel and then compared to discuss the need for a multi-criteria assessment of daylight-driven human responses in architecture. A parallel and comparative approach can allow the designer to adapt the architectural space based on the program use and occupants needs.
... It is generally agreed upon that visual and cognitive processing occurs during fixations, when the retinal image from the visual environment is stabilised. Very few studies so far have investigated the relationship between gaze shifts and building-induced visual context, such as the presence of window (Sury et al. 2010, Hubalek & Schierz 2004 or light (Kokoschka & Haubner 1985, Jakubiec & Reinhart 2012, Vincent et al. 2009, Nuthmann & Einhäuser 2015. These studies suggest that gaze directions extend over different regions of the space on vertical and horizontal planes and thus are not solely fixed on a certain area (Hubalek & Schierz 2004) . ...
... Very few studies so far have investigated the relationship between gaze shifts and building-induced visual context, such as the presence of window (Sury et al. 2010, Hubalek & Schierz 2004 or light (Kokoschka & Haubner 1985, Jakubiec & Reinhart 2012, Vincent et al. 2009, Nuthmann & Einhäuser 2015. These studies suggest that gaze directions extend over different regions of the space on vertical and horizontal planes and thus are not solely fixed on a certain area (Hubalek & Schierz 2004) . In other studies the necessity of limited luminance ratios at workplaces have been underlined for minimising performance losses due to re-adaptation process caused by dynamics of gaze direction (Kokoschka & Haubner 1985). ...
A gaze-driven methodology for discomfort glare was developed and applied for glare evaluation. A series of user assessments were performed in an office-like test laboratory under various lighting conditions. The participants’ gaze responses were recorded by means of mobile eye tracking while monitoring photometric quantities relevant to visual comfort using HDR luminance imaging. The integration of the luminance images coupled with eye-tracking methods enabled us to use gaze-centred luminance distribution to have an accurate estimate of the light received at the eye. Using a novel gaze-driven approach, a unique database was created as a basis to investigate the gaze direction dependencies of visual comfort. Here we compare the roposed gaze-driven approach with two other approaches based on fixed-gaze assumptions: gaze fixating on the task area, and gaze shifted 45 ° towards the window area. The results show that there is a significant difference between luminance distributions driven by gaze and those based on fixed-gaze assumptions, indicating a potentially important impact on glare assessment results as well.
... Although different eye movement classes coexist and interact with each other, up to recently studies of eye movements during natural perception have mainly focused on saccades with constrained head and body. Surprisingly few studies can be found on the relationship between eye movements and building-induced visual context, such as a window [72], and none of these linked eye movements to comfort perception until very recently [73][74][75]. ...
Daylighting as a research topic situates itself at the interface between psycho-physiological and environmental factors, bringing together questions relevant to architectural design and building engineering, but also to human physiology and behavior. While daylighting has a strong impact on human health and well-being, and an undeniable association with (subjective) emotional delight and perceived quality of a space, it is also highly dynamic and variable in nature, based on a combination of predictable (sun course) and stochastic (weather) patterns. This makes it both a challenging and essential aspect of how “performative” a space can be considered.
... On the other hand, direction of gaze is intrinsically related to the type of task (i.e. cognitive demands and task complexity) besides lighting [26,27]. Several factors affect pupil size, including the accommodative state of the eye [28], the observer's age [29] and the monocular versus binocular vision [30]. ...
The degree of eye opening (DEO) is proposed as a new indicator of glare in sunny climates in the presence of direct sunlight. A laboratory experiment was carried out (n = 20) in a simulated office space where volunteers performed computer office tasks. Four lighting situations, based on ranges of vertical illuminance at the eye level were evaluated. By means of a visible spectrum eye-tracker DEO was registered in each scenario. The proposed indicator was obtained by mathematical iterations and showed a good correlation with: vertical illuminance at the eye (r = −0.503; α = 0.0001), Daylight Glare Probability (DGP) (r = −0.649; α = 0.0001) and Glare Sensation Vote (GSV) (r = −0.580; α = 0.0001). This new indicator operates in a broad range of lighting conditions, from a low vertical illuminance at the eye scenario with diffuse daylight to a very high vertical illuminance at the eye scenario with uncontrolled direct sunlight. The proposed new indicator satisfies the following criteria: high validity, reliability, diagnostic power and acceptability and it also addresses unresolved aspects of current glare predictive models: GSV, DGP and DGI.
... If the person takes a break from the computer, his or her vision is directed towards the window. 22,23 However, glare has also been associated with the displacement of vision with respect to the glare source. 14 In addition, blinking plays a role in protecting the ocular globe against external aggression such as excessive light, heat, cold and dust. ...
This article studies the ocular behaviour of office workers in the presence of glare. Additionally, the
study seeks to obtain a new indicator for glare prediction that compensates the inaccuracies of glare
predicted by the existing models of glare sensation vote (GSV), daylight glare probability (DGP) and
daylight glare index. A laboratory experiment was carried out (n¼18) simulating an office space. The
volunteers participated in four office tasks (reading from a screen and from a paper, writing and
socializing). Two scenarios were evaluated: one with sunspots on the faces of the subjects and the
other with sunspots on the working area. By means of a visible spectrum eye tracker these ocular
parameters were registered: direction of gaze, the degree of opening of eye and pupil size. These
ocular parameters were correlated with vertical illuminance at the eye. The results show that the
degree of reduction of opening of the eye was the best predictor of visual discomfort with statistically
significant differences between scenarios (p¼–0.728, s¼0.001). The other important predictor was the
pupil size. The degree of opening of eye and pupil size was correlated with glare indices. The degree of
eye opening has a good correlation with GSV and DGP and it could be a future index of visual comfort
under situations of the risk of glare.
... 24 These studies suggest that gaze extends over different regions of the space on vertical and horizontal planes and thus is not solely fixed on a certain area. 25 In other studies with a focus on electric lighting of interiors, the necessity of limiting luminance ratios at workplaces has been underlined for minimising performance losses that are caused by the re-adaptation process as the gaze redirects. 17 This adaptive capability of gaze shifts in response to uncomfortable conditions was also acknowledged (somewhat arbitrarily) by extending gaze directions to a predefined angular range rather than to a unique gaze direction. ...
... We know that the task can override both discomfort sensation 25,[44][45][46] and gaze behaviour. 35,47 Therefore, we designed a sequence of office tasks to include components of an everyday work with explicit instructions, while leaving enough room for unconstrained visual exploration. ...
... Eye-movement analysis is used in fields such as car safety, surgery, software usability, product design, and also in assessing glare from monitor screen. Very few studies so far haveFigure 1 investigated the relationship between eye movements and building-induced visual context, such as a window [5, 6]. None went as far as connecting findings on eye-movements patterns to glare perception. ...
Discomfort glare, among different aspects of visual discomfort is a phenomenon which is little understood and hard to quantify. As this phenomenon is dependent on the building occupant's view direction and on the relative position of the glare source, a deeper knowledge of one's visual behavior within a space could provide pertinent insights into better understanding glare. To address this need, we set up an experiment to investigate dependencies of view direction distribution to a selected range of brightness and contrast distributions in a standard office scenario. The participants were asked to perform a series of tasks including reading, thinking, filling in a questionnaire and waiting. The direction of their view was monitored by recording participants' eye movements using eye-tracking methods. Preliminary results show that different facade configurations have different effects on the eye movement patterns, with a strong dependency on the performed task. This pilot study will serve as a first step to integrate eye-tracking methods into visual comfort assessments and lead to a better understanding of the impact of discomfort glare on visual behavior.
Data on the exposure of the human eye to light can help researchers and design professionals to better understand building performance with regards to the well-being and health of users. However, technologies currently used to evaluate indoor lighting conditions from a fixed point of view and measure luminous quantities are unable to map out visual scenes in a similar way to the human eye. With the aim of contributing to overcome this gap, this paper presents "OcuLux", a wearable device made in Brazil, designed to continuously monitor pupilar illuminance for indoor environments. "OcuLux" was calibrated and the sensor was worn for 7 days in November 2016 at the Solar Energy and Building Physics Laboratory (LESO-PB) at École Polytechnique Fédérale de Lausanne (EPFL) Lausanne campus (Switzerland), under partly cloudy and overcast skies to diagnose the light dose received by a person performing typical office activities. The results showed that no significant differences were found between the light dose received in the morning and in the afternoon. Although "OcuLux" has a limited measuring range, its use in a real situation has indicated that it is reliable for measurements of pupilar illuminance.
Discomfort glare is a major challenge for the design of workplaces. The existing metrics for discomfort glare prediction share the limitation that they do not take gaze direction into account. To overcome this limitation, we developed a ‘gaze-driven’ method for discomfort glare assessment. We conducted a series of experiments under simulated office conditions and recorded the participants’ gaze using mobile eye tracking and the luminance distributions using high dynamic range imaging methods. The two methods were then integrated to derive ‘gaze-centred’ luminance measurements in the field of view. The existing ‘fixed-gaze’ and the newly developed ‘gaze-driven’ measurement methods are compared. Our results show that there is a significant difference between the two methods. In this paper, the procedure for integrating the recorded luminance images with the recorded gaze dynamics for obtaining gaze-centred luminance data is described. This gaze-centred luminance data will be compared to the subjective assessment of glare in Part 2 of this study.
