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Lighting at computer workstations
Abstract
Background:
The visual conditions for computer work are complex and include several factors that need to be well controlled. These factors include the lighting system, thed esign of the computer and screen itself, the screens position and orientation within the room, the surface reflectances and colours of the room, and the visualability of the worker.
Objective:
The objective was to review the literature (including standards) on lighting for computer work in an accessible summary. This contribution focuses on lighting for computer work, but the reader is reminded of the fact that lighting continuously interacts with the other factors mentioned above.
Results/conclusion:
The combined visual conditions shall enable the worker to see and perform the work task without causing unnecessary strain for the eyes or the other parts of the body. The main lighting-related factors in the visual environment to evaluate are: illuminance, luminance, direction of light, glare, correlated colour temperature of the light source (CCT), colour rendering of the light source, and the non-visual effects (such as non-visual flicker). A visual ergonomics checklist is presented as a guide to analyse the visual environment.
... Another important ergonomic aspect of importance in office environments are visual conditions, including the lighting system, the position of computer monitors, and the visual acuity of the worker (Robertson et al. 2016). Under optimal conditions, workers are capable of performing tasks without straining the eyes (Osterhaus et al. 2015). Several visual changes can occur during human ageing, such as presbyopia, decreased contrast sensitivity, and delayed glare recovery (Peiyi 2014;Erdinest et al. 2021), therefore visual ergonomics at the workplace might affect younger and older workers differently. ...
... These results illuminate the need to take various needs into account when designing visual ergonomics in the office (Peiyi 2014;Erdinest et al. 2021). The choice of lighting design and control strategies for lighting depends on different factors, such as the number of workers who use the surface, the visual tasks to be performed, and the visual abilities of occupants; e.g., age or other conditions affecting vision (Osterhaus et al. 2015). Before relocation, all cell offices were located along the façade, with direct access to windows and daylight. ...
... Visual comfort has been shown to impact productivity, health, and overall comfort among office workers (Peiyi 2014;Robertson et al. 2016;Candido et al. 2019). Our results exemplify the importance of providing good visual ergonomics via a lighting design with sufficient indirect lighting and the availability for direct lighting where needed, especially for older workers (Osterhaus et al. 2015). To our knowledge, there are no previous longitudinal studies investigating the effects of visual comfort in AFOs, and further studies are needed. ...
Objective
This study aimed to investigate and explore Occupational Health and Safety (OHS) management, office ergonomics, and musculoskeletal symptoms in a group of office workers relocating from cell offices to activity-based flex offices (AFOs).
Methods
The analysis was based on qualitative interview data with 77 employees and longitudinal questionnaire data from 152 employees.
Results
Results indicate that there was a need to clarify roles and processes related to the management of OHS. Self-rated sit comfort, working posture, and availability of daylight deteriorated and symptoms in neck and shoulders increased after the relocation and seemed to be influenced by many factors, such as difficulties adjusting the workstations, the availability of suitable workplaces, and age, sex, and individual needs.
Conclusion
Research on the long-term effects of physical work environments and management of (OHS) issues after implementing activity-based flex offices is sparse. This study demonstrates the importance of planning and organising OHS issue management when implementing an AFO, and to carefully implement office ergonomics among office workers.
... Various factors affect visual and musculoskeletal problems in computer users, including physical environment factors (lighting, ergonomics, and workplace design), work task factors (subject matter, vision, contrast, and readability), and visual ability factors (visual acuity, age, and visual impairment) influence the visual environment of people [5][6][7]. The visual work environment can also impact human productivity in different ways [5]. ...
... Furthermore, non-visual exposure, such as flicker and glare from materials and work surfaces [27,28], lamps [29], screens, or windows, can cause eye discomfort and reduce visual performance or other visual disturbances such as headaches [7,30]. Studies have found that glare is associated with visual disturbances that are clearly linked to neck and shoulder pain. ...
BACKGROUND
In workplaces heavily reliant on visual tasks, various factors can significantly influence an individual’s performance, necessitating the use of reliable tools to identify and mitigate these factors.
OBJECTIVE
This study aimed to develop a swift assessment method for visual ergonomics and lighting conditions, evaluating its validity in real-world scenarios.
METHODS
The questionnaire’s content validity was determined by a panel of experts using the content validity ratio (CVR) and content validity index (CVI). Construct validity was assessed through exploratory factor analysis (EFA), confirmatory factor analysis (CFA), and latent class analysis (LCA). Internal consistency was measured using Cronbach’s alpha coefficient. The RAVEL index, derived from the calculated effect coefficients of items, classified total scores through receiver operator curves (ROCs).
RESULTS
The rapid assessment method, comprising two parts with 30 items, demonstrated acceptable reliability with CVR, CVI, and Cronbach’s alpha coefficient ( α ) at 0.75, 0.87, and 0.896, respectively. The EFA on the first part’s 22 items identified three factors, confirmed by CFA. The LCA on the second part’s eight items revealed that a two-class model best fit the data, with Bayesian information criterion (BIC) = 24249, 17, Akaik information criterion (AIC) = 2179.89, and an entropy R-squared of 0.83, indicating appropriate subject classification based on the model. The RAVEL score was categorized into three levels, with optimal cut points of 55 and 63.
CONCLUSIONS
In conclusion, the study demonstrated that this method based on visual ergonomics serves as a rapid and reliable tool for assessing visual ergonomic risks of display users in the workplace.
... The research suggests nine prototypes with different window-sill heights and WWRs. The prototypes are evaluated using computer simulation [12][13][14][15][16][17]. ...
... The tasks performed in classrooms need specific illuminance values depending on the type and nature of the task. According to the European National Standard (EN 12464-1:2002), the writing and reading task needs 300 lux on the horizontal plane (desks plane) and 500 lux on the vertical plane (the board), while the practicalrelated tasks such as handicraft, arts and experiments need 500 lux [16,[18][19][20]. Table 1 summarizes the illuminance values required by each task taking place in the classrooms. ...
... Previous studies have reported that adverse visual conditions cause musculoskeletal discomfort [31][32][33]. Sonographers often turn the light on and off during and between examinations, and it takes longer to adapt from one lighting level to another with increasing age [32]. Sonographers have also reported that perceived poor lighting, e.g. ...
... Previous studies have reported that adverse visual conditions cause musculoskeletal discomfort [31][32][33]. Sonographers often turn the light on and off during and between examinations, and it takes longer to adapt from one lighting level to another with increasing age [32]. Sonographers have also reported that perceived poor lighting, e.g. ...
Background:
Sonographers have reported a high occurrence of musculoskeletal pain for more than 25 years. Assessments of occupational risk factors have previously been based on cross-sectional surveys. The aim of this longitudinal study was to determine which factors at baseline that were associated with neck/shoulder and elbow/hand pain at follow-up.
Methods:
A questionnaire was answered by 248 female sonographers at baseline and follow-up (85% of the original cohort). 208 were included in the analyses. Physical, visual, and psychosocial work-related conditions were assessed at baseline. Pain in two body regions (neck/shoulders and elbows/hands) was assessed at both baseline and follow up.
Results:
Pain at baseline showed the strongest association with pain at follow-up in both body regions [prevalence ratio (PR) 2.04; 95% confidence interval (CI) 1.50-2.76], for neck/shoulders and (PR 3.45; CI 2.29-5.22) for elbows/hands. Neck/shoulder pain at follow-up was associated with inability of ergonomic adjustments at the ultrasound device (PR 1.25; CI 1.05-1.49), a high mechanical exposure index (PR 1.66; CI 1.09-2.52), and adverse visual conditions (PR 1.24; CI 1.00-1.54) at baseline. Moreover, among participants with no neck/shoulder pain at baseline, high job demands (PR 1.78; CI 1.01-3.12), and a high mechanical exposure index (PR 2.0; CI 0.98-4.14) predicted pain at follow-up. Pain in the elbows/hands at follow-up was associated with high sensory demands at baseline (PR 1.63; CI 1.08-2.45), and among participants without pain at baseline high sensory demands predicted elbow/hand pain at follow-up (PR 3.34; CI 1.53-7.31).
Conclusion:
Pain at baseline was the strongest predictor for pain at follow-up in both body regions. We also found several occupational factors at baseline that were associated with pain at follow-up: inability to adjust equipment, adverse visual conditions, a high MEI, high job demands and high sensory demands. These results point at a possibility to influence pain with better ergonomics.
... In this way, luminaires are not located in front of or above the worker, shining in their eyes and creating discomfort from direct glare [24,25]. Nor are the luminaires directly behind the worker casting shadows on the workstation [26] or producing specular or diffuse reflections on the computer displays which can reduce contrast and task visibility and contribute to visual discomfort [27]. ...
... The second design convention is to not have large differences in luminance contrast between objects; otherwise the brightness difference between objects can be distracting [26] and contribute to visual discomfort [29]. Examples of non-optimal conditions which could be experienced by mobile workers include working near windows or luminaires which are significantly brighter than the digital display, or the reverse: using a digital display in low light conditions where the display is significantly brighter than the surroundings. ...
Mobile technology has revolutionised how we work. It is now relatively easy to work anywhere and anytime, but this has placed the onus is on mobile (or flexible) workers to set up their own work environment for comfort and ease of use. Vision is an important driver of posture, and hence visual ergonomics principles are integral for setting up digital devices. If mobile workers do not have visual ergonomics knowledge, or are unable to apply visual ergonomics knowledge to appropriately set up their work environment, then they are at risk of developing visual-related occupational health issues due to exposure to adverse physical work environments. To address this potential health care issue, we propose the introduction of Visual Ergonomics Health Literacy. This would provide mobile workers (including school children) with the knowledge and skills to set up their work environment for comfort and ease of use, wherever they work. It is important to address this issue now before we have a widespread epidemic of discomfort and injury from not applying sound visual ergonomics principles to work environments.
... The results of the VCL index show that not only illuminance and CCT are important factors affecting the light environment quality of the office, but that the screen brightness of electronic equipment is also an important factor affecting the overall work quality. Moreover, with the development of science and technology and the popularization of electronic office equipment, the proportion of screen brightness is also increasing [55], which is becoming increasingly important in the quality evaluation of the overall working environment of the office. ...
With the development of modern technology, many people work for a long time around various artificial light sources and electronic equipment, causing them to feel discomfort in their eyes and even eye diseases. The industry currently lacks an objective quantitative environmental–visual comfort index that combines subjective and objective indicators. For this experiment, objective eye movement and electroencephalogram (EEG) signals were collected in combination with a subjective questionnaire survey and a preference inquiry for comprehensive data mining. Finally, the results on a Likert scale show that high screen brightness can reduce the visual fatigue of subjects under high illuminance and high correlated color temperature (CCT). Pupil data show that, under medium and high ambient illuminance, visual perception sensitivity is more likely to be stimulated, and visual fatigue is more likely to deepen. EEG data show that visual fatigue is related to illuminance and screen brightness. On this basis, this study proposes a new evaluation index, the visual comfort level (0.6404 average at a low screen brightness, 0.4218 average at a medium screen brightness, and 0.5139 average at a high screen brightness), where a higher score for the visual comfort level represents a better visual experience. The visual comfort level provides a useful reference for enhancing the processing of multi-dimensional and biomedical signals and protecting the eyes.
... When monitoring the light environment with electronic screens, we found that for more than 85% of the participants, the ambient light exceeded 4,000 K color temperature at night, and it exceeded 6,000 K color temperature for more than 35% of the participants. Several studies (34,35) have suggested that high-color temperature lighting at night disrupts the melatonin secretion cycle, influences sleep in Frontiers in Public Health 08 frontiersin.org Distribution of ambient lighting color temperature during screen time. ...
Background
Myopia poses a global health concern and is influenced by both genetic and environmental factors. The incidence of myopia tends to increase during infectious outbreaks, such as the COVID-19 pandemic. This study examined the screen-time behaviors among Chinese children and adolescents and investigated the efficacy of artificial intelligence (AI)-based alerts in modifying screen-time practices.
Methods
A cross-sectional analysis was performed using data from 6,716 children and adolescents with AI-enhanced tablets that monitored and recorded their behavior and environmental light during screen time.
Results
The median daily screen time of all participants was 58.82 min. Among all age groups, elementary-school students had the longest median daily screen time, which was 87.25 min and exceeded 4 h per week. Children younger than 2 years engaged with tablets for a median of 41.84 min per day. Learning accounted for 54.88% of participants’ screen time, and 51.03% (3,390/6,643) of the participants used tablets for 1 h at an average distance <50 cm. The distance and posture alarms were triggered 807,355 and 509,199 times, respectively. In the study, 70.65% of the participants used the tablet under an illuminance of <300 lux during the day and 61.11% under an illuminance of <100 lux at night. The ambient light of 85.19% of the participants exceeded 4,000 K color temperature during night. Most incorrect viewing habits (65.49% in viewing distance; 86.48% in viewing posture) were rectified swiftly following AI notifications (all p < 0.05).
Conclusion
Young children are increasingly using digital screens, with school-age children and adolescents showing longer screen time than preschoolers. The study highlighted inadequate lighting conditions during screen use. AI alerts proved effective in prompting users to correct their screen-related behavior promptly.
... As to the type of glare source reflected in Q1-Q4, the sensation of visual 456 discomfort might be led by different types of stimuli in our given situations, including 457 the veiling glare from extreme luminance contrast (e.g., between the surface of a 458 window illuminated by diffuse daylight or direct sunlight and a darker adjacent 459 computer display screen), the veiling reflection in the monitor from the brightness in 460 daylit area, or the electronic screen luminance itself led by its contrast setting or the 461 interactive effect with correlated color temperature (CCT) [97]. [108 , 109 , 110 ] . ...
Previous studies have shown the inconsistent performance of various daylighting glare prediction metrics in office daylit-dominated environments. This lack of consensus may stem from a limited understanding of how their component variables contribute to the prediction power reflected on these discomfort glare models. Previous studies predominantly focused on individual variables’ linear, independent impact on glare discomfort prediction, neglecting to explore their non-linear and interaction contributions. This study addressed these limitations by evaluating regularly used glare variables using machine learning-based feature selection and SHAP interpretation methods to parse the collected dataset in a subjective survey. By applying different machine learning algorithms and SHAP explainers, we have identified their contribution importance to the prediction of different scales of glare discomfort rating when incorporated into one model and have observed the difference of interaction effects between these variables on predicting glare discomfort ratings. Our findings indicate that vertical eye illuminance, maximal luminance, and window mean luminance exhibit strong prediction power and significant interaction effects on glare discomfort sensations, indicating that they could be the dominant contributors to glare predictive metrics. Contrast effect variables within the field of view had less predictive influence on glare scales when combined with other variables. This innovative approach enables a comprehensive assessment of different variables’ influential sequence and interaction consequences when incorporated into the glare prediction model. It facilitates the development of the new glare discomfort prediction model.
... The light source coming from behind the digital device screen, such as light coming from the window, can be adjusted by changing the location of the digital device so that the light behind the digital device is not brighter than the light from the digital device screen. The next step is to use lamps whose lighting is diffuse to reduce reflections on surfaces that can cause glare (Osterhaus, Hemphala and Nylen, 2015). ...
Introduction Since the COVID-19 pandemic in Indonesia, many activities have been carried out online from home. This change in activity causes the frequency of gadget use to increase. Looking constantly at gadgets such as laptops, desktops, and mobile phones can risk visual problems or visual fatigue. Aims: this research is to describe visual fatigue and the factors that affect students due to the increasing use of gadgets. Methods This study is a quantitative study with a cross-sectional approach—collected data from April to June 2021. The sample in this study was 200 people. The variables are visual fatigue, viewing distance, eye breaks, and refractive error. Data were collected using a questionnaire distributed to respondents using google Forms. Data were analyzed by univariate and bivariate with 95% CI (α = 0.05). Result The analysis showed that 87% of students experienced visual fatigue, 76% used gadgets at an unsafe distance, 92% did not rest their eyes, 39.5% had refractive errors. Statistical test results between visual fatigue with viewing distance (p-value = 0.53), eye breaks (p-value = 0.04) and refractive error (p-value = 0.44). There is a relationship between eye breaks and visual fatigue. Based on the results of this study, take eye breaks by applying 20-20-20, namely resting the eyes every 20 minutes by turning the eyes to see objects as far as 20 feet for 20 seconds when using gadgets to reduce the risk of visual fatigue.
... Along with the developments in computer technologies, the primary work surface in office environments has been shifted from horizontal desk surface (where writing and reading tasks were predominant) to vertical computer screen surface. However, lighting installations have not yet completely responded to this change yet (Osterhaus, Hemphälä & Nylén, 2015). ...
This dissertation proposes a holistic, multi-dimensional approach for analysing task performance by understanding the psychological, physiological and cognitive performance-based changes with respect to various lighting quality factors. The main objective was to observe and integrate these three categories of potential affecting variables into the evaluation of overall task performance of video display terminal (VDT) users. In the existing literature, specifically in daylit offices, human behaviour and physiology are not sufficiently considered while evaluating task performance, or vice versa, performance changes in VDT users are not often taken into consideration while behavioural and psychological processes are analysed.
This PhD dissertation describes different stages of conception of this holistic method that includes objective performance measures coupled with ocular and behavioural responses, in order to overcome the limitations associated with the subjectivity and individuality aspects of lighting effects for analysing occupants’ task performance. The assessments were done in a series of experiments in a mock-up office setting under different (day)lighting conditions where participants’ ocular behaviour as well as their subjective assessments were recorded while monitoring photometric quantities including vertical illuminance at the eye and luminance data. In the first experimental phase, an initial study was made for proper integration of the adopted methods and techniques regarding ocular behaviour into visual comfort assessments. Development of several algorithms and tools to identify and translate the ocular behaviour in order to derive the actual luminous distribution perceived by the participants were needed to achieve this goal. In the next comprehensive experimental phase, the impact of daylight illuminance and luminance on various physiological, performance and psychological measures during visual display terminal work was explored. Additionally, the results from the relationships between photometric variables and physiological and subjective responses as well as performance measures are presented. The developed approach demonstrates the need to integrate ocular patterns and human behaviour into task performance assessments, which move us beyond the existing rigid and rough design approaches towards a holistic, human-centric lighting design in computerized offices.
... Shiny things, like paper, glass, and computer screens, can cause veiling reflections. As several computer screen uses in larger spaces, care needs taking to prevent reflections of light from the screens inside the task area (Osterhaus W. H., 2015). For lighting design, it is critical to understand how different viewing directions will be affected by the placement of permanent luminaires. ...
Purpose: Evaluate human performance under LED lighting system in commercial building regarding:-Visual Performance (VP), Motor Performance (MP), Task Performance (TP), Cognitive Performance, Human Performance, and Work Life. To assess the direct effect between Cognitive Performance and Human Performance To identify the role of Circadian System (M1), and Discomfort (M2) between Cognitive Performance and Human performance. Theoretical framework: Driven lighting is presently the most reliable. As a result, determining all crops' light needs is complicated. Purposive sampling use to select the respondents. Floor office units and single office rooms required LED illumination. Because the entire population list was unavailable, 200 samples chose for the investigation. The study looked at an employee's cognitive and human performance. No relation between visual and cognitive performance. Pain impairs cognitive and motor functions. No discomfort affects work-life balance. However, the pain reduces human performance. Distress, eye pain, and weariness impede human performance. However, visual discomfort, visual message, glare, and flicker do. The study recommends assessing visual performance based on employee illumination discomfort. Design/Methodology/Approach:Driven lighting systems are now the most widely used and dependable in the world. Compact fluorescent light bulbs are used in India's current lighting systems for the most part. Even though there are a few small and medium-sized LED producers, there is no industry standard for LED production. As a result, estimating the amount of light all types of produce require is difficult. The goal of this research was to find out how LED illumination affects human performance. An organized questionnaire was utilized to gather information from employees of various government and commercial sector organizations. The research focused on the Trivandrum area because Trivandrum is Kerala's capital and home to most of the state's administrative offices. Respondents were drawn from government and private sector offices using a stratified random sampling approach. Offices were divided into floor office units and single office rooms, with LED lighting systems required in all of them. Two hundred samples were chosen for the study after the reliability and genuineness of obtained data were checked because the entire population list was unavailable. Findings: Research, Practical & Social Implications: As a result of this research, we set out to determine how well LED and conventional (linear fluorescent, compact fluorescent, and incandescent) lighting systems perform luminously, how well people perform, and how much they cost in the most common luminaire applications currently found in the environment. The popularity of LED lighting systems has overtaken that of all other kinds of fabricated luminaires. In contrast, linear and compact fluorescent luminaires are used in most Indian lighting systems now in use. No LED standards exist, despite just a handful of medium and small firms currently producing LED lights. As a result, establishing the precise illumination requirements for each product is challenging to do. Compare the environmental, technological, and economic factors to the alternatives now accessible to discover a better solution. Originality/value: Human performance is very much important in every sector and it’s depended on various multi-dimensional factors. Here the study has been analysed the direct and indirect effect between Cognitive Performance and Human performance of an employee. Simultaneously, study is saying that cognitive performance is not depending on the visual, and task performance. On the other hand, it could be seen that, Cognitive performance is affected by discomfort and the motor performance influence towards the Cognitive performance is positive but not significant. In the case of work life, it has no influence towards the human performance and also discomfort is influencing the human performance. While analyzing the mediation effect, it was found that, direct effect of Cognitive Performance will increase the Human Performance, but the existence of discomfort will reduce the human performance. Which means that negative mood change, visual discomfort, discomfort to visual message, Glare, Flicker, Eye pain, and fatigue are reducing the human performance. Based on the findings from the study, it could be seen that visual, motor and task performance is not influencing the cognitive performance, at the same time visual discomfort, discomfort to visual message, Glare, Flicker are decreasing their performance. hence, the study is suggesting that visual performance should be measure on the basis of various discomforts faced by the employee from their work place lightening.
... 16,17 Epidemiological studies have identified illuminance and CCT as particularly pertinent factors in the development of asthenopia. 18,19 The illuminance and CCT of LEDs for illumination applications should therefore be of specific concern and need to be designed appropriately, so that possible risks and levels of discomfort can be minimised. 20,21 Numerous recent studies have examined the health impact of LEDs and their effect on asthenopia. ...
Purpose
A self‐controlled study to determine the influence of illuminance and correlated colour temperature (CCT) of light‐emitting diode (LED) lighting on asthenopia.
Methods
Twenty‐two healthy postgraduates (nine women) were recruited to read under eight LED lighting conditions with four illuminances (300 lx, 500 lx, 750 lx and 1000 lx) and four CCTs (2700, 4000, 5000 and 6500 K) for 2 h. A subjective asthenopia questionnaire, the optical quality analysis system (OQAS) and an inflammatory cytokine assay were used to assess the levels of asthenopia.
Results
Increased asthenopia was observed after reading, but the degree varied with lighting conditions. There were significant differences among the groups in terms of subjective symptoms (inattention, eye pain, dry eye and total score), optical performance parameters (modulation transfer function [MTF] cut‐off frequency, Strehl ratio [SR], objective scattering index [OSI], mean OSI and accommodative amplitude [AA]) as well as inflammatory cytokines in the tears (epidermal growth factor [EGF], transforming growth factor [TGF]‐α, interleukin [IL]‐6, IL‐8, macrophage inflammatory protein [MIP]‐1β, tumour necrosis factor [TNF]‐α, TNF‐β and vascular endothelial growth factor [VEGF]‐A). All of the subjective and objective measurements collectively suggested that asthenopia was lessened for the 500 lx–4000 K condition. However, asthenopia was significantly worse for 300 lx–2700 K and 1000 lx–6500 K in terms of subjective symptoms and objective optical performance, respectively.
Conclusions
LED illuminance and CCT do have a significant effect on asthenopia during reading. 500 lx–4000 K lighting resulted in the lowest level of asthenopia. Conversely, low illuminance at low CCT (300 lx–2700 K) and high illuminance at high CCT (1000 lx–6500 K) promoted more severe asthenopia.
... Furthermore, non-visual exposures such as flickering light sources may cause eye strain and headaches. The visual environment should be designed to allow natural light to enter but block out disturbing light [3]. Glare, when working with a computer, causes visual fatigue and can lead to diplopia [1], which is measured by the divergence of vision stabilization [2], which means a decrease in the ability of the eyes to concentrate [4]. ...
The purpose of this study was to model the visual ergonomic factors affecting the performance in human computer interaction. A cross-sectional study using structural equation modelling was performed with a sample of 200 participants. The measuring instruments included Office Lighting Survey Questionnaire, performance assessment questionnaires, visual ergonomics assessment, and an eye discomfort assessment. The hypothetical model evaluated workplace lighting status and visual ergonomics as precursors, performance as the output, and eye discomfort as a mediator. The results showed that eye discomfort directly affected performance. Visual ergonomics also had a significant direct effect on eye discomfort. The final model suggested a significant new path between the quality of lighting and visual ergonomics. Also, the quality of lighting had an indirect effect on eye discomfort and performance, and the effect of visual ergonomics on performance was the same. Improving the lighting quality and visual ergonomics can reduce eye discomfort and increase performance.
... The basic lighting design for most typical office spaces provides mostly general lighting which is intended to light up the spaces (de Bakker, Aries, Kort, & Rosemann, 2017;Raynham, 2016). Some offices provide task lighting where the lighting source is targeted for task-specific (Raynham, 2016) such as lighting at a computer workstation (Osterhaus, Hemphälä, & Nylén, 2015). Task and general lighting aside, other lighting sources are designed for various purposes. ...
The purpose of this qualitative descriptive study was to understand how workers describe the interior design and the design dimensions of a remodeled office space as it relates to workplace satisfaction in central Arizona. The overarching research question was: How do workers describe the interior design and design dimensions of a remodeled office space as it relates to workplace satisfaction? The sample included workers of a remodeled office space located in central Arizona who completed a questionnaire and participated in an interview. The theoretical foundation was the theory of perceived satisfaction. The instruments for data collection included a questionnaire and a semi-structured interview. The data sources included data from the questionnaire, interviews, and photographs of the interior design and design dimensions of the office space. The data analysis included thematic analysis and descriptive statistics. The findings from this study provided insights into how the interior design and design dimensions relate to workplace satisfaction. Recommendation for future research included an investigation on how the organization’s values, culture, and play a role in influencing the interior design of an office space attributed to workplace satisfaction; an investigation on the design of open office concept and factors of open office concept that lead to positive workplace satisfaction; an investigation on the effects of a pandemic related to workplace satisfaction and the evolution of impacts on a post-pandemic work environment and space use; as well as an investigation on the relationship of open office concept or shared workspace to workplace satisfaction in a post-pandemic world.
... The lighting quality for computer work is dependent on several factors, such as illuminance, luminance, direction of light, glare, light source, screen design, and users' visual ability (c.f. review by Osterhaus et al., 2015). Improper lighting, visual display position, and viewing distance contribute to "the computer vision syndrome" (eye strain, dryness, and neck and shoulder pain). ...
Online distance learning is offered not only in post-secondary distance education institutions but in traditional universities as well. With advances in mobile and wireless technologies, completing academic studies anywhere anytime should become feasible. Research in distance education and online learning has focused on computer-mediated communication, instructional design, learner characteristics, educational technology, and learning outcomes. However, little attention has been given to where exactly learners do their learning and studying and how the physical and social aspects of the physical environment within which the online learner is physically embedded (e.g., the home) supports and constrains learning activities. In this paper, the author proposes a conceptual model for understanding the role that the physical environment plays in online distance learning in higher education, drawing on theories and research in environmental psychology, online learning, telework and mobile work, and higher education. Several gaps in research are identified, and suggestions for future research are proposed.
... The level of discomfort appears to increase with the amount of digital screen use [3]. Visual discomfort and related symptoms occurring in computer workers must be recognized as a growing health problem [4].The visual conditions for computer work are complex and include several factors that need to be well controlled [5]. Computer users vision-related problems are the most frequently reported health-related problems occurring in over 70% of computer users [6], [7].The most common symptoms associated with Computer Vision Syndrome CVS or (DES) are eyestrain, headaches, blurred vision, dry eyes, neck and shoulder pain, while the symptoms may be caused by poor lighting, glare on a digital screen, improper viewing distances, poor sitting posture and uncorrected vision problems [3]. ...
The increasing number of cases of ocular and non-ocular symptoms generally termed, the "Computer Vision Syndrome" (CVS) as a result of the ubiquitous use of computers and mobile computing devices. Computer-related asthenopia might take an epidemic form if it is not put on check. This study was undertaken to find out the prevalence of the visual complaints among computer and related users in Owerri, Imo State aimed at determining if the symptoms are prevalent in equal proportion among VDU and Non-VDU users. A total of 332 selected persons (male and female) between the ages of 16-45yrs from schools, banks, offices and other establishments who use VDUs≥and <1hr/day within Owerri Municipal Area were administered with structured questionnaire. Study revealed VDU users presentation with Headache (17.72%), Ocular Pain (16, 52%), Eyestrain (15.40), Lacrimation (14, 60%), Double Vision (11.75%), Burning &Irritation (10.09%), Itching (7.83%), Dryness (3.58%) and Redness (2.52%). All the Symptoms (dryness, eyestrain, headache, itching, lacrimation, ocular pain and redness) except double vision are statistically significant (P<0.05). Furthermore, these symptoms are neither age nor gender related. Also, individuals as well as work-related factors were found to be predictive of these visual complaints. Headache, ocular pain, eyestrain, lacrimation, double vision, burning & irritation, itching, dryness and redness of the eye are the prevalent symptoms among VDU users in Owerri. The use of antiglare screen, filters or "radiation absorbing devices' to reduce and control light and reflections as well as adjustment shades, curtains or blinds in order to effectively control light levels throughout the day are however recommended.
... Contrast glare induced by i.e., computer screens, reflected light or fluorescent lamps within the field of view were present in eight of the nine control rooms (for detailed illuminance-and luminance values, see Table 4). Accordingly, since high luminance differences were present in those control rooms the operators eyes probability had difficulty staying adapted to the luminance of the work task which caused eye discomfort and/or disability glare [38]. The recommendation of the uniformity within the room, i.e., working area, is a ratio of higher than 0.7 (maximum and minimum luminance) [36]. ...
Background:
Working in front of computer screens is visually demanding and related to adverse eye symptoms. Occurrence of glare further increases visual fatigue.
Objective:
This paper presents results from an examination of visual ergonomics in control room environments at two Swedish process industries.
Methods:
Visual conditions were examined and evaluated in nine control rooms and eighteen process operators answered questions about their perceived workload and visual experiences.
Results:
When working in the control rooms, the mental workload was rated significantly higher by the participants, compared to experienced performance. The operators further experienced significantly higher visual fatigue and blurred vision compared to double vision and sore eyes. Visual demands were increased in conditions where contrast glare was present, as well as frequent changes of focusing distances, and low contrast between background and characters in computer screens.
Conclusions:
Suboptimal visual working conditions in the control rooms contributes to increased visual demands on the operators. Presence of glare is leading to visual fatigue and an unnecessary high mental load. The findings support the relevance of considering principles of general and visual ergonomics when designing and organizing work in control rooms. Workstation design should also be flexible to allow for individual and contextual adjustments.
... Glare from luminaries or windows may cause discomfort and reduced performance in visually demanding work tasks (Anshel, 2007;Rosenfield, 2011). In addition, non-visual exposures such as flicker from luminaries may cause eyestrain and headache (Osterhaus et al., 2014). Although mostly recognized in computer work (Blehm et al., 2005;Dainoff et al., 2005;Habibi et al., 2014;Shieh and Lin, 2000), the impact of high visual demands on workers' well-being has been demonstrated in other types of occupations as well (Bogdanova et al., 2016;Fritzsche et al., 2012;Hemphälä, 2014;Juslén and Tenner, 2005;Lindegård et al., 2012Lindegård et al., , 2016. ...
Objective
To describe the development of a computer-based risk assessment method for visual ergonomics, and assess its face validity, content validity, and internal consistency.
Methods
The risk assessment method contained a questionnaire for the worker, an evaluation form for the evaluator, a section of follow-up questions based on the worker's responses, and a section for recommended changes, including an overall risk assessment with respect to daylight, lighting, illuminance, glare, flicker, work space, work object and work postures, respectively. Forty-eight trained evaluators used the method to perform 224 workplace evaluations. Content validity of the method was assessed by the completeness and distribution of responses, and internal consistency was assessed by Cronbach's alpha, Spearman's rank correlation between items and indices, and exploratory factor analysis.
Results
The proportion of missing values in items was generally low (questionnaire: 0–2.3%; evaluation form: 1.4–4.1%). In the questionnaire, items about double vision, migraine and corrective lenses had limited information content. Cronbach's alpha and item-index correlations for the indices frequency of eyestrain, intensity of eyestrain, visual symptoms, lighting conditions, frequency of musculoskeletal discomfort and intensity of musculoskeletal discomfort were satisfactory. Based on the factor analysis, suggestions for improving some of the indices were made.
Conclusion
Our findings suggest that this computer-based method is a valid instrument for assessing risks in the visual work environment. By incorporating subjective ratings by the worker as well as objective measurements of the work environment, it provides a good basis for recommendations with respect to daylight, lighting, work surfaces/material, and work object.
Relevance to industry
Visual environment factors, such as glare, can cause eyestrain, headache and musculoskeletal discomfort. This method satisfies the need of a valid tool for determining risks associated with the visual work environment. It contains both worker's ratings and objective measurements, and is designed to be used in different types of work.
... lighting, ergonomics, and workplace design), the work task (e.g. the work object, visibility, contrasts and readability), and the individual's visual ability (e.g. visual acuity, age, and visual defects) (Anshel, 2005;Blehm et al., 2005;Gowrisankaran and Sheedy, 2015;Long, 2014;Osterhaus et al., 2015). To evaluate and improve visual ergonomics at workplaces and prevent visual and musculoskeletal problems, all these factors need to be assessed. ...
Introduction
The Visual Ergonomics Risk Assessment Method (VERAM) is a newly developed and validated method to assess visual ergonomics at workplaces. VERAM consists of a questionnaire and an objective evaluation.
Objective
To evaluate reliability of VERAM by assessing test-retest reliability of the questionnaire, and intra- and inter-rater reliability of the objective evaluation.
Methods
Forty-eight trained evaluators used VERAM to evaluate visual ergonomics at 174 workstations. The time interval for test-retest and intra-rater evaluations was 2–3 weeks, and the time interval for inter-rater evaluations was 0–2 days. Test-retest reliability was assessed by intraclass correlation (ICC), the standard error of measurement (SEM) and the smallest detectable change (SDC). Intra- and inter-rater reliability were assessed with weighted kappa coefficients and absolute agreement. Systematic changes were analysed with repeated measures analyses of variance and Wilcoxon sign rank test.
Results
The ICC of the questionnaire indices ranged from 0.69 to 0.87, while SEM ranged from 7.21 to 10.19 on a scale from 1 to 100, and SDC from 14.42 to 20.37. Intra-rater reliability of objective evaluations ranged from 0.57 to 0.85 (kappa coefficients) and the agreement from 69 to 91%. Inter-rater reliability of objective evaluations ranged from 0.37 to 0.72 (kappa coefficients) and the agreement from 52 to 87%.
Conclusion
VERAM is a reliable instrument for assessing risks in visual work environments. However, the reliability might increase further by improving the quality of training for evaluators. Complementary evaluations of VERAM's sensitivity to changes in the visual environment are needed.
Relevance to industry
It is advantageous to set up a work environment for maximal visual comfort to avoid negative effects on work postures and movements and thus prevent visual- and musculoskeletal symptoms. This method, VERAM, satisfies the need of a valid and reliable tool for determining risks associated with the visual work environment.
... Glare from luminaries or windows within the visual field can cause disability glare and/or discomfort glare (Anshel, 2007;Rosenfield, 2011). The visual environment must be designed to allow natural light coming in, but have the ability to prevent disturbing light (Osterhaus et al., 2015). Glare while performing tasks on the computer causes visual fatigue and can lead to strabismus measured by fixation disparity, i.e. decreased ability for the eyes to focus (Glimne et al., 2013). ...
... Common light hazards in the cleanroom environment include poor lighting, special lamp design (e.g., yellow light), high illuminance (e.g., microscope), and low illuminance (e.g., light-on test) [4]. These hazards may result in lighting problems, such as disability glare, discomfort glare, flicker, and veiling reflections, and cause eye discomfort [6][7][8]. Toomingas et al. indicated that non-optimal visual conditions (e.g., poor lighting, glare) was an independent risk factor for eye symptoms [9]. Although prior studies reported that dry eye symptoms at the workplace are associated with poor lighting, female gender, cleanroom, long employment duration, family history of atopic disease, and low humidity [5,10,11], the association between different lighting problems and eye symptoms among cleanroom workers is rarely addressed. ...
The visual health of microscope workers is an important occupational health concern, and a previous study suggested an association between lighting problems (e.g., flashing light, insufficient lighting) and eye symptoms among cleanroom workers in the electronics industry. This study aimed to explore the association between eye symptoms and lighting problems, as well as light-related counteracting behaviors among microscope workers in the cleanroom environment. Ninety-one cleanroom workers aged 20 years or older were recruited from an electronics factory. The socio-demographic factors, work-related factors, eye symptoms, and lighting problems were assessed using a self-administered questionnaire. There were 92.3% female participants in this study. Among all participants, 41.8% and 63.7% had symptoms of dry eye and eye fatigue, respectively. The counteracting behaviors of needing to move closer (adjusted odds ratio (aOR) = 3.47, 95% CI = 1.11 to 10.88) was significantly associated with dry eye symptoms. Workers who were more experienced at the job (aOR = 1.03, 95% CI = 1.01 to 1.06) and had shorter break times (aOR = 0.94, 95% CI = 0.91 to 0.98) were more likely to have eye fatigue. As a result of these findings, this study suggests that good lighting and adequate break times are crucial to improve the visual health of cleanroom microscope workers.
... Ergonomics should be considered if no contributing ocular or general health conditions are identified and eye strain symptoms do not resolve with basic treatment. 22 Research also highlights how the use of devices such as smartphones and tablets can contribute to visual stress. Smartphone users were found to move the viewing distance of their phones closer with prolonged use (60 minutes or more), increasing eye strain symptoms in some users. ...
... Also, in the same study, they found that the minimum:maximum ratios as fallen as 0.5 in the center of the desk would be acceptable for most of the occupants. Besides of earlier studies, CIBSE (1987) explains the recommended illuminance uniformity as the following standards given below: Especially at computer workstations, luminance balance is one of the main factors in lighting design influencing visual performance (Osterhaus, Hemphälä, and Nylén, 2015). Visual complaints of Visual Display Unit (VDU) operators are found to be increasing over the years and along with the growing use of VDU in workplaces, decrease in performance resulting from high luminance or irregular luminance ratios in the occupant"s field of view has been recently standing as a significant problem that needs to be paid attention (Piccoli et al., 2015). ...
Higly glazed facades has been increasing with the intention of more daylight gain in buildings. However, more daylight may not always bring more satisfaction considering many factors that influence daylighting quality. Uncontrolled daylight brings visual and thermal problems which end up with negative interactions with user comfort. Library spaces in which different task activities are performed simultaneously need to be well designed in terms of daylight performance, thus the user satisfaction could enhance.
This thesis particularly focuses on the optimization of visual performance in an academic library with a new layout arrangement and a light shelf-reflective louver system. One of the reading rooms of Izmir Institute of Technology Library was chosen as a reference case, where the instrumental monitoring of existing daylighting conditions was performed. The reference case was then analyzed with daylight simulation tool, so that the outcomes would later be used for the performance testing of the new proposals. Luminance patterns and illuminance distribution of different points were evaluated in terms of visual performance recommendations. A new layout arrangement and light shelf-reflective louver system were proposed respectively in accordance with the deficiencies of simulation results. Ultimately, daylight performance of the library was significantly improved regarding illuminance and luminance based distribution.
Despite a diminution in average illuminance due to the dramatic decrease of excessive amount of daylight near the window, the big picture gives the clues on how a simple layout change and a daylighting system can make enhancement on the visual performance of a library reading room.
People with photosensitive epilepsy may have seizures caused by flashing lights, patterns, and video sequences. Because of this, there is increasing interest among researchers, developers, and companies towards making content safer. There are five major guidelines (from the U.K., Japan, ISO, ITU, and W3C) to limit risk in different technology domains that have been created since the mid-1990s. All address similar risk factors, but they are not fully harmonized and can be confusing. Furthermore, there have been significant changes in technology since the guidelines were introduced. This paper compares and clarifies the guidelines, describes risk factors that have changed (such as the reduction of risk due to display technology), gaps in our knowledge, the coverage of new technology, and new characteristics (such as the duration and synchronicity of individual flash transitions) that may need to be accounted for. The authors suggest working values for new thresholds and propose updated guidelines.
In hot climates, such as sub-Sahara Africa, window sizing and orientation pose challenges as they add, through solar insolation, to the building cooling energy demand and thus the cause of indoor overheating risk. This risk can be reduced through passive building-design-integrated measures, e.g., optimizing the window size, orientation and solar shading strategies. Through an IDA-ICE building performance simulation tool, the current study explores the impact of window size, optimization and building-integrated PV panels as shading strategies on cooling energy demands in three cities (Niamey, Nairobi and Harare) in sub-Sahara Africa. Results show that thermal comfort and cooling energy demand are sensitive to a window-to-wall ratio (WWR) > 70%, while the need for artificial lighting is negligible for a WWR > 50%, particularly in the north for cities in the Southern hemisphere and the south in the Northern hemisphere. A WWR > 70% in the east and west should be avoided unless shading devices are incorporated. Internal blinds perform better in improving occupant thermal comfort but increase artificial lighting while integrating PV panels, as external shading overhangs reduce cooling energy but also produce energy that can be utilized for building services, such as air conditioning. In this study, the results and implications of the optimization of window size, orientation and building-integrated shading and operation are discussed.
Denna slutrapport presenterar resultaten av projektet Betydelsen av en optimerad synergonomi för ett hållbart kontrollrumsarbete. Projektet har genomförts under tre år mellan 2017 och 2020.
Synergonomi handlar om samspelet mellan vår syn, ljuset och objektet vi tittar på. Dator- och bildskärmsarbete som ställer höga krav på syn och koncentration ökar. God synergonomi på arbetsplatsen är därför betydelsefullt för både medarbetarens hälsa och för hur väl arbetet kan utföras.
Syftet med detta forskningsprojekt var att kartlägga synergonomin i olika typer av kontrollrum och baserat på synergonomiska riktlinjer utforma praktiska råd och rekommendationer för hur synergonomiska risker vid kontrollrumsarbete kan minskas.
En kartläggning har genomförts i 20 kontrollrum vid nio företag. Fem företag är sysselsatta med trafikledning och fyra är olika typer av processindustrier.
Totalt deltog 56 kontrollrumsoperatörer (19 kvinnor och 37 män). Bland annat har belysningsnivå, luminans, risk för bländning, växlingar i synavstånd, betraktnings-vinklar, samt bildskärmars synbarhet utvärderats. Operatörerna har också besvarat frågor om upplevd syn- och arbetsbelastning.
Resultaten visar att operatörerna upplever högre synkrav och något högre grad av ögonbesvär i kontrollrum där det förekommer kontrastbländning, upprepade förändringar av fokuseringsavstånd och låg kontrast mellan tecken och bakgrund på skärmen. Arbetsuppgifterna i kontrollrummen upplevs främst som mentalt belastande.
En jämförelse mellan de två branscherna pekar på att operatörer i processindustrin hade färre möjligheter till anpassning av sina arbetsplatser och hade fler uppåtriktade blickriktningar jämfört med operatörer i trafikledning. Operatörerna inom process-industrin rapporterar också något högre grad av ögonbesvär.
Resultaten stöder tidigare forskning om vikten av att arbetsplatser och arbets-uppgifter anpassas efter människors förmågor och begränsningar. Långvarigt höga synkrav leder till ökad ögontrötthet och onödigt hög mental belastning. För ett hållbart arbetsliv med allt fler som arbetar högre upp i ålder behöver anpassningen även omfatta åldersrelaterade synnedsättningar.
A smart luminaire able to change the direction of its light beam is installed in an office environment and compared to the available LEDs fixtures. Standard lighting measures are performed and a controlled user experiment is conducted, involving 22 subjects. Qualitative results suggest that very low illuminance levels can be characterized as comfortable. Quantitative results supported by statistical significance reveal (1) wider use range of illuminance levels for the smart luminaires, (2) an interaction decrease during the experiment and (3) different usage of the luminaire depending on the subject’s side. Advantages and drawbacks of digitally actuated luminaires are briefly discussed.
It is now widely accepted in the research community, and increasingly so amongst practitioners, that the standards/guidelines for daylight in buildings are in need of upgrading. The basis for the majority of EU guidelines is the half-century-old daylight factor. The daylight factor (DF) considers relative illumination under a single overcast sky. Thus the DF is insensitive to prevailing climate and orientation of the building or site. Attempts to advance standards beyond the daylight factor have, so far, met with limited success. There are a number of reasons for this, one of the most significant being that, with one largely overlooked exception, it appears to be impossible to advance the DF methodology by incremental means. The incremental advances that have been suggested include the various 'clear sky options' described in LEED and ASHRAE. The basis for these approaches appears to be flawed if not actually unsound. It is now widely acknowledged that climate-based daylighting modelling offers the means to make a major advancement in the evaluation of daylight in buildings. Climate-based daylight modelling (CBDM) delivers predictions of luminous quantities under realistic sun and sky conditions. Climate-based metrics have been used effectively on a number of projects large and small, e.g. from the New York Times Building to residential dwellings. CBDM tools however are either the preserve of research/experts or freely-available but largely unsupported. Whilst metrics founded on CBDM will almost certainly form the basis for daylight standards in the medium term (some are already appearing), there is a pressing need to progress current practice in the short term, i.e. the next few years. Specifically, the authors propose that a long-overlooked method linking the estimation of daylight provision to prevailing climate be used as the basis for guidelines and standards. The method, founded on cumulative diffuse illuminance curves, could be introduced relatively swiftly since it requires only modest enhancement of existing daylight prediction tools. And, importantly, it will provide a sound 'footing' for eventual progression to evaluations founded on full-blown climate-based daylight modelling.
When driving at night, flickering automobile LED tail lights can appear as multiple images. The perception of a flickering source of light was therefore studied during rapid eye movements (saccades) of 20–40° amplitude in an otherwise dark room (<1 lux). The temporal modulation appeared as a spatial pattern known as a ‘phantom array’ during the saccade. The appearance of the pattern enabled the discrimination of flicker from steady light at frequencies that in 11 observers averaged 1.98 kHz. At a frequency of 120 Hz, the intrasaccadic pattern was perceptible when the contrast of the flicker exceeded 10%. It is possible that intrasaccadic stimulation interferes with ocular motor control.
The weekly incidence of headaches among office workers was compared when the offices were lit by fluorescent lighting where the fluorescent tubes were operated by (a) a conventional switch-start circuit with choke ballast providing illumination that pulsated with a modulation depth of 43-49% and a principal frequency component at 100 Hz; (b) an electronic start circuit with choke ballast giving illumination with similar characteristics; (c) an electronic ballast driving the lamps at about 32 kHz and reducing the 100 Hz modulation to less than 7%. In a double-blind cross-over design, the average incidence of headaches and eyestrain was more than halved under high-frequency lighting. The incidence was unaffected by the speed with which the tubes ignited. Headaches tended to decrease with the height of the office above the ground and thus with increasing natural light. Office occupants chose to switch on the high-frequency lighting for 30% longer on average.
To study the joint occurrence of eye-and-neck/scapular area symptoms and their association with occupational risk factors in a cross-sectional sample of professional information technology users.
The participants consisted of 3,971 employees who worked with computers for a minimum of one hour a day. 2,551 (73%) were men and 945 (27%) women, with an age range of 18 up to 64 years. The mean age was 38.1 (SD=10.7) for men and 37.6 (SD=12.0) for the women. The measures were obtained via a self-administered survey in combination with a visual examination conducted by an optometrist.
Two complementary logistic regression analyses with forced entry was conducted on n=3,496 (88% adjusted response rate) cases. The effect of ocular symptoms on the risk of reporting musculoskeletal symptoms, or vice versa, was examined first in two separate binominal logistic regression analyses. Age, Gender, Near work variable and Visual functioning variables were included in these analyzes. Variables associated with the risk of developing an increase in either symptom category were also examined in two additional binomial logistic regression analyses.
Exposure to spectacles (single vision, multifocal, or progressive correction) in combination with a visual acuity <1 surfaced as a key mediator of symptoms from the neck/scapular area (p<0.01). A vergence disparity (uncompensated vergence error) similarly was associated with an augmented risk of developing an increase in neck/scapular area symptoms (p<0.05). The most influential risk factor for neck/scapular area symptoms were ocular symptoms and vice versa (p<0.0001).
The results support the hypothesis which postulates that eye-neck/scapular area symptoms interaction may be due to a functional coupling from and between the eye-neck/scapular area muscles [28].
This paper describes two experiments concerning the effects of variations in lighting quality on office worker performance, health, and well-being. Experiment 1 had four experimental conditions: a regular array of fully direct recessed parabolic luminaires; direct/indirect luminaires with no control; direct/indirect luminaires with a switchable desk lamp; and, workstation-specific direct/indirect luminaires with control over the direct portion. Experiment 2 contrasted two conditions with no individual lighting control: a regular array of recessed prismatic lensed luminaires, and suspended direct/indirect luminaires. Participants considered the direct/indirect systems to be more comfortable than the direct-only systems, with a further increase in comfort associated with individual control in Experiment 1. There were no simple main effects of lighting quality on the performance of any task, although the expected changes in performance associated with task visibility, practice, and fatigue were found. Interactions between lighting quality and time suggested that having a degree of individual control of lighting tended to maintain motivation and vigilance over the day.
OBJECTIVES: Few, if any, studies have investigated whether eyestrain and shoulder–neck symptoms are correlated, although functional links could be expected on the basis of neurophysiological evidence. This cross-sectional study assessed correlations between self-reported eyestrain and shoulder–neck symptoms among call center workers, while controlling for possible confounders for these ailments. METHODS: A questionnaire concerning socioeconomic background, work conditions, and symptoms was mailed to 1531 employees at 28 different call centers during 2001–2003. RESULTS: Altogether 21% of the responding participants (N=1183) reported both eyestrain and neck–shoulder symptoms, 46% reported neck–shoulder symptoms only, and 6% reported eye symptoms only; 27% were free from symptoms in these regions. A significant positive association was found between eyestrain and neck–shoulder symptoms. Significant covariates for shoulder–neck disorders were eyestrain (OR 1.6, P=0.007), gender (to be female) (OR 1.9, P
This study investigated the effect of moving from single occupancy offices to a landscape environment. Thirty-four Visual Display Unit (VDU) operators reported significantly worsened condition of lighting and glare in addition to increased visual discomfort. For visual discomfort, the difference with 95% confidence interval was 10.7 (1.9-19.5) Visual Analog Scale (VAS) as group mean value. The most reasonable explanation for these results may be that the operators were glared from high luminance from the windows, when the Venetian blinds were not properly used. Glare was significantly correlated with visual discomfort, rs=0.35. Both illuminance and luminance in the work area, and contrast reduction on the VDU screen were in line with recommendations from CIE for VDU work. In a regression analysis, the visual discomfort explained 53% of the variance in the neck and shoulder pain. In the office landscape, the eye blink rate during habitual VDU work was recorded for 12 randomly selected operators from the 34 participants. A marked drop in eye blink rate during VDU work was found when this was compared to "easy conversation" (VDU work, mean=9.7 blinks per minute; "easy conversation," mean=21.4 blinks per minute). Participants reported many of the organizational and psychosocial conditions and work factors worse when landscape office was compared to single occupancy office. These factors may have influenced the musculoskeletal pain. However, the pain level was still low at 6 years and not significantly different when compared with the start of the study period, except for a small but significant increase in shoulder pain. In this study, visual discomfort is clearly associated with pain in the neck and shoulder area.
Now updated and expanded to cover the latest technologies, this full-color text on clinical refraction uses an easy-to-read format to give optometry students and practitioners all the important information they need. Also covers a wide range of other aspects of the eye exam, including anterior and posterior segment evaluations, contact lens, ocular pharmacology, and visual field analysis. Four new chapters cover wavefront-guided refraction, optical correction with refractive surgeries, prosthetic devices, and patients with ocular pathology. Offer precise, step-by-step how-to's for performing all of the most effective refractive techniques. Presents individualized refractive approaches for the full range of patients, including special patient populations. Contriubtors are internationally recognized, leading authorities in the field. New full-color design with full-color images throughout. Completely updated and expanded to include current technologies. A new chapter on Optical Correction with Refractive Surgeries, including keratoplasty, traditional refractive surgeries (e.g. LASIK and PRK), crystalline lens extraction with and without pseudophakia, the new presbyopic surgery, etc. A new chapter on Wavefront Guided Refraction provides information on the advantages and limitations the Hartmann-Shack Method for objective refraction plus aberrometry and the refraction and the use of in the correction of the eye with spectacles, contact lenses, and refractive surgery. A new chapter on Patients with Ocular Pathology reflects the most current knowledge of patients with ocular pathologies. Provides information on Optical Correction with Prosthetic Devices, including corneal onlays, stromal implants, phakic intraocular lenses, etc. Includes new chapters and/or discussions on such topics as: Aberrations of the Eye, Refractive Consequences of Eye Pathology, Diagnosis and Treatment of Dry Eye, Diagnosis of Pathology of the Anterior Segment, Diagnosis of Glaucoma, and Diagnosis of Pathology of the Posterior Segment. Visual Acuity chapter expanded to include the effect of refractive error on visual acuity and statistics on how much of a change in visual acuity is significant. Objective Refraction, Corneal Topography, and Visual Field Analysis chapters include the addition of new electro-optical and computer techniques and equipment. Chapters on Multifocal Spectacle Lenses and Contact Lenses now cover newer progressive addition lenses and contact lenses that are now on the market. Electrodiagnosis chapter revised to take a more clinical approach.
Architecture and design students are frequently required to establish suitable lighting conditions for the buildings and spaces they design as part of their studio courses. While lighting design guidelines are available, students find out quickly that lighting quality is a complex issue that cannot be assessed by simple equations or rules-of-thumb. Balancing the many and often contradictory aspects of energy efficiency and high quality lighting design is a complex undertaking not just for students. The work described in this paper is one result of an academic staff exchange between the Schools of Architecture in Copenhagen (Denmark) and Victoria University of Wellington (New Zealand). The authors explore two approaches to teaching students simple assessment methods that can contribute to making more informed decisions about the luminous environment and its quality. One approach deals with the assessment of luminance ratios in relation to computer work and presents in that context some results from an experiment undertaken to introduce the concept of luminance ratios and preferred luminance ranges to architecture students. In the other approach a Danish method for assessing the luminance distribution within a visual field is discussed. Students participating in the experiments began to understand how quantitative measures relate to qualitative experiences, a skill that is likely to be very useful in later architectural or design practice.
This book covers all aspects of daylighting in commercial, institutional, industrial, and residential buildings. All types of buildings in all geographic areas are examined, with extensive case studies, models, analytical tools, and data for calculation of annual cost and energy savings also included. This book also features newly developed computer, factorial, graphic, and modeling analysis techniques. Twenty-two appendices provide data on sunlight availability for 75 cities, overlays, analysis formulas, nomograms, material reflectances, illuminance categories, and cooling-load factors. In brief this book also describes the building design process.
This paper proposes a multidisciplinary approach to solving computer related vision issues by including optometry as a part of the problem-solving team.
Computer workstation design is increasing in complexity. There are at least ten different professions who contribute to workstation design or who provide advice to improve worker comfort, safety and efficiency. Optometrists have a role identifying and solving computer-related vision issues and in prescribing appropriate optical devices. However, it is possible that advice given by optometrists to improve visual comfort may conflict with other requirements and demands within the workplace. A multidisciplinary approach has been advocated for solving computer related vision issues. There are opportunities for optometrists to collaborate with ergonomists, who coordinate information from physical, cognitive and organisational disciplines to enact holistic solutions to problems. This paper proposes a model of collaboration and examples of successful partnerships at a number of professional levels including individual relationships between optometrists and ergonomists when they have mutual clients/patients, in undergraduate and postgraduate education and in research. There is also scope for dialogue between optometry and ergonomics professional associations.
A multidisciplinary approach offers the opportunity to solve vision related computer issues in a cohesive, rather than fragmented way. Further exploration is required to understand the barriers to these professional relationships.
The authors studied the effect of a large area light source of
variable but uniform luminance surrounding a video display terminal on
the perceived glare discomfort and visual performance of computer
operators. A set of criteria was established for rating the discomfort.
Source luminance adjustments by means of a variable transformer to match
the subjective glare criteria, as well as ratings of preselected
lighting conditions on a visual analog scale with the same criteria,
were used to determine comfortable lighting conditions. Results from the
experiment indicate that subjects reliably selected a preferred lighting
condition at any time when asked to adjust the luminance to produce
optimum visual comfort. Subjects preferred higher luminances following
high initial presentation luminances. Performance speed at a difficult
letter-counting task suggest that visual performance was slightly
impaired by the presence of glare discomfort. Counting errors also
occurred slightly more frequently under higher surround source
luminances. There was a tendency for subject to become more susceptible
to glare over the course of the experiment
A survey of physical work conditions was performed in a strategic sample of call centres in Sweden. Extensive observations including measurements of work environment factors took place at 16 companies, involving 156 operators and their workstations. Observed conditions were compared with current directives and recommendations and also with the operators’ ratings of comfort and reported symptoms. Internal and external call centres working in the whole range of task complexity were compared.The air quality and thermal climate in the workplace were mainly satisfactory, but air humidity was low. Sound levels were often high at many workstations and illuminance too low. Glare and reflexions in the VDU-screens were common. The observations indicate that the conditions quite often were out of range of current directives and recommendations for sound working environment. The indoor climate, the air quality, the ambient noise level and the illumination created dissatisfaction of comfort among about 74% the operators. Correlations between the ratings of comfort and the observations were moderate, but most were statistically significant. No significant associations between symptoms (eyes, ears, throat, skin or headache) and the observations were found.Relevance to industryThe study provides useful data both for designing call centres and similar offices and for improvement of the physical work environment. It points out which physical factors and environment-related symptoms one should be especially aware of among call centre workers.
To provide a multidisciplinary synthesis of scientific information on disability, discomfort, dazzling, and scotomatic (photostress) glare.
Perspective.
Analysis and integration of relevant historical and contemporary publications on glare in ophthalmology, illumination engineering, neurology, and other relevant disciplines.
Disability glare is caused by scattered intraocular light (straylight) not useful for vision. Straylight casts a veiling luminance on the retina, reducing image contrast and impairing vision. In common environments, glare and target illumination sources have the same or similar spectra. Colored spectacle or intraocular lens filters reduce both proportionately, so they do not increase retinal image contrast or decrease disability glare. Discomfort glare is caused by situational illumination too intense or variable. Dazzling glare occurs when high illuminances are spread across the retina. Neurophysiological research is clarifying how discomfort and dazzling glare depend on different retinal photoreceptors and nociceptive brain pathways involving the trigeminal ganglion and thalamus. Photostress is caused by excessive local retinal photopigment bleaching uncommon in ordinary situations. Optical glare countermeasures are available for daytime driving but not oncoming automobile headlights at night. Filters that decrease daytime discomfort or dazzling glare also reduce nighttime mesopic and scotopic sensitivity.
Glare is problematic for patients and clinicians despite a century of scientific research. Advances in understanding glare have been hampered by its complex, multidisciplinary nature and limited interdisciplinary communication. We provide one pathway through the forest of glare nomenclature and mechanisms. Improved diagnostic and therapeutic methodologies await continuing progress in understanding glare.
Visual requirements are high when sorting mail. The purpose of this visual ergonomics intervention study was to evaluate the visual environment in mail sorting facilities and to explore opportunities for improving the work situation by reducing visual strain, improving the visual work environment and reducing mail sorting time. Twenty-seven postmen/women participated in a pre-intervention study, which included questionnaires on their experiences of light, visual ergonomics, health, and musculoskeletal symptoms. Measurements of lighting conditions and productivity were also performed along with eye examinations of the postmen/women. The results from the pre-intervention study showed that the postmen/women who suffered from eyestrain had a higher prevalence of musculoskeletal disorders (MSD) and sorted slower, than those without eyestrain. Illuminance and illuminance uniformity improved as a result of the intervention. The two post-intervention follow-ups showed a higher prevalence of MSD among the postmen/women with eyestrain than among those without. The previous differences in sorting time for employees with and without eyestrain disappeared. After the intervention, the postmen/women felt better in general, experienced less work induced stress, and considered that the total general lighting had improved. The most pronounced decreases in eyestrain, MSD, and mail sorting time were seen among the younger participants of the group.
This is the second report in a major epidemiologic health investigation on work with a video display terminal (VDT). The first study showed that VDT operators reported more eye discomfort than a reference group not employed in VDT work and that women reported more eye discomfort, musculoskeletal complaints, headache, and skin disorders than men, regardless of whether they worked with a VDT or not. The present report contains the results of the occupational hygiene measurements (indoor climate, lighting and electrostatic conditions). Considerable differences were found between VDT operators and referents and also between sexes. Indications were obtained of a possible relationship between eye discomfort and luminance ratios in the working field of vision. Otherwise, no association could be established between occupational exposure factors and subjective eye discomfort, musculoskeletal complaints, headache, or skin disorders.
Flicker in solid-state lighting: Measurement techniques, proposed reporting and application criteria
- M E Poplawski
- N M Miller
Poplawski ME, Miller NM. Flicker in solid-state lighting:
Measurement techniques, proposed reporting and application
criteria. Proceedings of CIE Midterm Conference -Towards
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