Working in front of visual display units, VDU, has become more and more common and an increasingly number of office workers spend a larger part of their working day in front of a monitor. Thus, work-related eye disorders associated with VDU use increase. Employers has a responsibility to prevent accidents and sickness among their employees, which partly can be done by risk assessments of visual ergonomic conditions at the office workplace. The purpose of this master thesis was to investigate how VDU office workers with, or without, eye- or neck problems perceive the lighting conditions in relation to how an ergonomist who has gone through a nine-day visual ergonomics education, assess the lighting. Data has been collected by 48 ergonomics specialists and work environment engineers who risk assessed 204 VDU stations at different offices in Sweden using a new visual ergonomics risk assessment method. The results showed several strong connections between the assessment made by the trained technician and the individual VDU workers perception of lighting conditions, such as the general lighting and glare. The technician noticed however more risks than the individual worker did. VDU workers with eye-strain reports more problems with their lighting conditions in the office compared to those without eye-strain. The technician’s assessment of glare, and the individual VDU worker´s experience of strong lights hade the most impact on reported eye-strain. VDU workers with neck pain did not report any problems with their lighting conditions in contrast to the technician who reported an increased risk at both general lightning and glare. / Att arbeta framför dator har blivit allt vanligare och allt fler arbetar stor del av sin arbetsdag framför en bildskärm. De arbetsrelaterade besvären i samband med detta ökar. Arbetsgivaren ska förebygga ohälsa och olycksfall vilket bland annat kan göras genom att riskbedöma synergonomiska förhållanden på kontorsarbetsplatsen. Syftet med examensarbetet var att undersöka hur individer med respektive utan ögon- eller nackbesvär vid bildskärmsarbete på kontor uppfattar sina belysningsförhållanden i relation till hur en ergonom som utbildats inom synergonomi och belysning under en 9 dagars utbildning bedömer belysningsförhållandet. Data är insamlat av 48 ergonomer och arbetsmiljöingenjörer som riskbedömt 204 bildskärmsarbetsplatser på olika kontor med hjälp av en ny synergonomisk riskbedömningsmetod. Resultatet visar att det finns flera starka samband mellan ergonomens bedömning och individens uppfattning av belysningsförhållandena, exempelvis gällande allmänbelysningen och bländningen. Ergonomen uppmärksammar dock fler risker än vad individen gör. Individer med ögonbesvär rapporterar i högre grad besvär med sina belysningsförhållanden på kontoret jämfört med individer utan besvär och den belysningsrelaterade faktor som har störst betydelse för om individen anger ögonbesvär är ergonomens bedömning och individens uppfattning av bländning/starka lampor. Individer med nackbesvär rapporterar inga större besvär med belysningsförhållandena i motsatts till ergonomen som rapporterar risker med både bländningen och allmänbelysningen.

The main aim of this thesis was to evaluate the performance of the contrast sensitivity clock (CSC), a new screening device for measuring contrast sensitivity (CS) and glare. This device allows CS without glare, with glare and disability glare scores to be recorded. After initial data collection the design of the CSC was slightly amended improving the performance of the device. The amended design of the CSC was shown to be a valid, discriminative and repeatable measure for purpose. The CSC is also a quick test to perform and is relatively cheap to produce. If all these factors are considered it shows potential to become the test of choice for the assessment of visual glare. A head-mounted display system was also evaluated in terms of the glare effects it may cause. The monocular display screen of the device significantly reduced the CS of the eye directly exposed but also had an effect on binocular performance, reducing amounts of binocular summation. Electronic devices, including head-mounted displays and satellite navigation systems can seriously affect CS at low luminance levels, similar to those found when driving at night.

Este trabalho tem como objetivo analisar estratégias de iluminação natural utilizadas nos estágios iniciais do projeto de arquitetura capazes de aumentar a qualidade da iluminação e a conservação de energia nos edifícios escolares. Essas estratégias têm sido aplicadas com sucesso em edifícios escolares em vários países, melhorando o desempenho e o bem-estar dos estudantes e conservando energia. Entre essas estratégias, o autor selecionou um dispositivo zenital para iluminação natural com seleção angular e difusores opacos, realizou um ensaio experimental em um modelo físico reduzido de uma sala de aula padrão, sob condições de céu real e analisou comparativamente os resultados. O estudo mostrou que a adoção de uma metodologia para utilizar estratégias como a analisada neste trabalho pode conseguir um adequado controle da radiação solar para evitar a incidência direta da luz do Sol, evitar o ofuscamento e o aquecimento excessivo de ambientes de salas de aula em climas quentes e, ao mesmo tempo, aproveitar a iluminação natural, tanto difusa quanto direta refletida, para obter maior conforto visual e economizar energia. / This work aims to analyse daylighting strategies applied in early stages of architectural design as to improve lighting quality and energy savings in school buildings. Similar strategies have already been successfully applied in many countries around the world, enhancing student?s performance and well being while helping to save energy. Among the strategies studied, the author describes an experiment under real sky conditions using a physical scale model of a standard classroom equipped with a roof monitor combined with an overhang and interior vertical diffusing baffles as a way to check its influence in interior lighting conditions. The experiment has shown that the use of daylighting strategies can promote an adequate control of solar radiation, avoiding direct sunlight penetration inside the classrooms, limiting glare problems and excessive heat of hot climates. At the same time, such strategies optimise both direct and defuse use of daylight to improve visual comfort and energy savings.

Este trabalho tem como objetivo analisar estratégias de iluminação natural utilizadas nos estágios iniciais do projeto de arquitetura capazes de aumentar a qualidade da iluminação e a conservação de energia nos edifícios escolares. Essas estratégias têm sido aplicadas com sucesso em edifícios escolares em vários países, melhorando o desempenho e o bem-estar dos estudantes e conservando energia. Entre essas estratégias, o autor selecionou um dispositivo zenital para iluminação natural com seleção angular e difusores opacos, realizou um ensaio experimental em um modelo físico reduzido de uma sala de aula padrão, sob condições de céu real e analisou comparativamente os resultados. O estudo mostrou que a adoção de uma metodologia para utilizar estratégias como a analisada neste trabalho pode conseguir um adequado controle da radiação solar para evitar a incidência direta da luz do Sol, evitar o ofuscamento e o aquecimento excessivo de ambientes de salas de aula em climas quentes e, ao mesmo tempo, aproveitar a iluminação natural, tanto difusa quanto direta refletida, para obter maior conforto visual e economizar energia. / This work aims to analyse daylighting strategies applied in early stages of architectural design as to improve lighting quality and energy savings in school buildings. Similar strategies have already been successfully applied in many countries around the world, enhancing student?s performance and well being while helping to save energy. Among the strategies studied, the author describes an experiment under real sky conditions using a physical scale model of a standard classroom equipped with a roof monitor combined with an overhang and interior vertical diffusing baffles as a way to check its influence in interior lighting conditions. The experiment has shown that the use of daylighting strategies can promote an adequate control of solar radiation, avoiding direct sunlight penetration inside the classrooms, limiting glare problems and excessive heat of hot climates. At the same time, such strategies optimise both direct and defuse use of daylight to improve visual comfort and energy savings.

This thesis deals with the evaluation of the quality of lighting with the usage of the latest software products used nowadays. The first part of the work is about indoor lighting, the basic requirements invested in lighting, and the basic concepts of indoor lighting. The second part includes complete search for today's computer implements for projecting, simulating, calculation and analysis of light, their functions and characteristics, including luminance analyzers based on CCD sensors and their software equipment. The last part of the work has the task to model a computer room using softwares which can be found within the territory of VUT Brno, and the task was to assess its lighting. Following this, with the help of luminance analyzer, the task is to capture the scene under different lighting conditions and to evaluate the measured data.

In recent years a number of cases of flight crew illumination by laser beam have been reported. Such events are considered dangerous for flight safety and for aviator´s health. If a human eye is illuminated by laser beam of high intensity such event can lead to temporary or permanent eye damage.

<p>Over the last two decades, an increasing number of highway construction and maintenance projects in the United States have been completed at night to avoid or mitigate traffic congestion delays. Working at night entails several advantages, including lower traffic volumes at night, reduced impact on local businesses, more freedom for lane closures, longer possible work hours, lower pollution, cooler temperatures for equipment and material, and fewer overall crashes due to lower traffic volumes at night. Although nighttime roadway operations may minimize traffic disruptions, there are several safety concerns for motorists passing by and for workers in the nighttime work zone. For instance, just in 2019, there were 842 work zone fatalities reported in the United States, with 48% of these being associated with fatalities on night shifts. Additionally, 70% of these fatalities involved drivers/occupants under the age of 50. Moreover, improper lighting arrangements or excessive lighting levels produced by temporary lighting systems installed at the job site could cause harmful levels of glare for the traveling public and workers leading to an increase level of hazards and crashes in the vicinity of the work zone. </p> <p>To address the issue of glare, very few studies have been conducted to evaluate and quantify glare at work zones. Most of these studies were limited to the determination of disability glare levels of lighting systems (balloon lights and light towers) with a metal-halide type light source by using the veiling luminance ratio (<em>VL ratio</em>) as a criterion for limiting disability glare. However, deeper evaluation of the effects of driver’s age on the veiling luminance ratio, and the use of energy-efficient lighting systems which employ light-emitting diode (LED) type light sources were not performed.</p> <p>This thesis focuses on determining and evaluating disability glare on nighttime work zones as a step towards developing appropriate lighting strategies for improving the safety of workers and motorists during nighttime highway construction and maintenance projects. Disability glare is the glare that impairs our vision of objects without necessarily causing discomfort and it can be evaluated using the veiling luminance ratio (<em>VL ratio</em>). In this study, disability glare values were determined by using lighting data (vertical illuminance and pavement luminance measurements) from testing 49 lighting arrangements. Two LED balloon lights, a metal-halide light tower, and an LED light tower were utilized for the field lighting experiments. The disability glare level evaluation examines the effects of mounting height, power output, rotation angle, and aiming angle of luminaires on the veiling luminance ratio values (which is a criterion for limiting disability glare). </p> <p>The analysis of the disability glare values revealed four major findings regarding the roles played by the mounting height, power output, lighting system orientation, aiming angles of luminaries, and driver’s age on disability glare levels as follows: (i) an increase in mounting heights of both balloon lights and light towers resulted in lower veiling luminance ratio values (or disability glare); (ii) compared to the "perpendicular" and "away" orientations, orienting the light towers in a "towards" direction (45 degrees) significantly increases the disability glare levels of the lighting arrangement; (iii) increasing the tilt angles of luminaires of the portable light towers resulted in an increase in veiling luminance ratio values; (iv) for balloon lights, at observers ages over 50, <em>VL ratio</em> values were found to be greater than the maximum recommended; (v) for LED light towers oriented towards the traffic, at driver’s ages over 40, <em>VL ratio</em> values exceed the Illuminating Engineering Society (IES) recommended value; and (vi) for metal-halide light towers oriented towards the traffic, at driver’s ages over 50, <em>VL ratio</em> values exceed the IES recommended value. The results from this research study can provide State Transportation Agencies (STAs) and roadway contractors with a means to improve glare control strategies for nighttime work.</p>

Idag byggs fler bostäder än vad som gjorts under de senaste 60 åren. Det finns många utmaningar med den volym bostäder som behöver byggas. Många bostäder kommer byggas i exploateringsområden, detta ställer krav på infrastrukturinvesteringar exempelvis i form av nya skolor. Enligt prognoser kommer antalet grundskoleelever öka med 250 000 till år 2025. Detta innebär ett behov av 1000 nya skolor på tio år. Behovet av skolor är långsiktigt och lärmiljöer behöver planeras för att vara långsiktiga. Dagsljus och utblick har en stor inverkan på vår arbetsmiljö, prestation och är nödvändig för vår hälsa. Studier har visat att dagsljusbelysta skolmiljöer får elever att prestera bättre. Trots detta har vi sedan 50-talet halverat kravet på dagsljusnivåer i skolor från 2 % till 1,0 % dagsljusfaktor. Idag har vi samma dagsljuskrav för klassrum som för ett sovrum i en bostad. Syftet med examenarbetet är att problematisera moderna skolmiljöer sett ur dagsljusets betydelse för hälsa och prestation i relation till dagens myndighetskrav för tillgång av dagsljus. Vidare syftar arbetet till att ta fram goda exempel på dagsljuslösningar som kan nyttjas vid utformning av moderna skolmiljöer. För att bedöma moderna skolors dagsljustillgång har ett urval av fem skolor i Stockholmsområdet utgjort studieobjekt där tillgången på dagsljus undersökts mot myndighetskraven. Undersökning av studieobjekten har utförts genom 3D modellering i Rhinoceros 3D samt dagsljusfaktorsimuleringar i programmet Grasshopper och Honeybee. Studieobjekten har modellerats upp efter inhämtade bygglovsritningar och dagsljussimuleringarna har utförts med simuleringsmotorn Radiance. Resultatet från dagsljusfaktorsimuleringen visar att ingen av de undersökta skolornas fullt ut uppfyller myndighetskraven. Anledningen till varför skolornas undersökta rum inte uppfyller kraven varierar mellan eller utgör en kombination av; rumsdjup, fönsterstorlek, fönstersättning i fasad, avskärmningsvinklar, avskärmande byggnadsdelar och fast solavskärmning. Undersökningen visar att rum som hemvistytor och uppehållsrum ofta saknar fönster mot det fria och följaktligen underkänns. Dessa rum är vanligt förekommande vid nyttjande av progressiva pedagogiska inriktningar. Beroende på rummens tilltänkta användning kan de komma att klassas som vistelserum och behöver därför tillgång till dagsljus. Ur litteraturgenomgången förstås att en tidig integrering av dagsljusdesign i gestaltningsprocessen är nödvändigt för att säkerställa en god tillgång till dagsljus i lärmiljöer. Som del av examensarbetet har därför ett gestaltningsförslag tagits fram där en dagsljusdesign nyttjas. Iterativt under gestaltningsprocessen har dagsljustillgång simulerats för att motivera gjorda designval och säkerställa en god dagsljusnivå. För jämförande och platsspecifika resultat har klimatbaserade simuleringsmetoder använts. Det nyttjade mätvärdet Optimal Day-lit Area (ODA) simulerar användbarheten i det tillgängliga dagsljusets belysningsstyrka över ett år. Samtidigt tar ODA hänsyn till överbelyst golvyta som kan vara problematisk då obehagsbländning och överhettning kan uppstå. Det presenterade gestaltningsförslaget utgör ett konceptförslag i syfte att gestalta användningen av en integrerad dagsljusdesignprocess och dess resultat. / Currently more housing is being built than in the past 60 years. There are many challenges accompanied with the volume of housing that needs to be built. Many of the dwellings that are going to be built are placed in new densely planned urban areas, which imposes requirements for infrastructure investments, for example in the form of new schools. According to forecasts, the number of students in primary school will increase by 250,000 by the year 2025. This implies a need for approximately 1000 new schools in ten years. The need for new schools are long term and therefore the learning environments need to be designed to be long term. Daylight and view have a major impact on our work environment, performance and are necessary for our health. Studies have shown that daylight-lit school environments enhance the performance of the students. The building legislation regulates the required levels using the daylight factor metric. Since the 50’s the requirements of daylight levels in schools have been approximately halved from 2 % to 1,0 %. Today the daylight requirements are the same for classrooms as for bedrooms in dwellings. The purpose of this thesis is to examine modern school environments in relation to today's regulatory requirements for access to daylight. Furthermore, the work aims to produce good examples of daylight solutions that can be used when designing modern school environments against the regulatory requirements. To assess the daylight access in modern schools, a selection of three nursery schools and two primary schools in the vicinity of Stockholm were chosen. Case studies were conducted using the 3D modelling software, Rhinoceros 3D and the daylight factor was then simulated using the Grasshopper and Honeybee plug-ins. The schools were modelled according to the acquired drawings and daylight were performed using the simulation engine Radiance. The result from the daylight factor simulation show that none of the schools examined fully meet the requirements. The reasons why the examined schools do not meet the requirements vary between or constitute a combination of; room depth, window size, window façade, obstruction angles, obstructing components and shading devices. The study shows that rooms such as: common areas and study hall often lack windows towards the outside and therefore only gets borrowed light from other areas. These kinds of rooms are common when using progressive pedagogical approaches. Depending on the intended future use of the rooms, they may be classified in such a way that they need to fulfil the regulations regarding daylight. From the literature review it is understood that early integration of daylight design in the design process is necessary to ensure good accesses to daylight in learnings environments. As a part of the thesis project, a design proposal has been developed using a daylight design process. During the design process, the access to daylight has been iteratively simulated to motivate selected design choices and ensure a good daylight level.  For comparison and site-specific results, climate-based simulation methods have been used. The use of the Optimal Day-lit Area (ODA) metric measures the usefulness of the available daylight illumination intensity over a year. At the same time, ODA takes the eventual over lit areas that may cause overheating and glare into account. The presented design proposal demonstrates the use of an integrated daylight design process and its results.

Doctor of Philosophy / Department of Industrial & Manufacturing Systems Engineering / Malgorzata J. Rys / This dissertation is the result of studying different methods of increasing guide sign visibility and legibility to drivers during nighttime, to increase safety on roadways. It also studies intersection lighting to indicate the lighting benefits on nighttime crash frequency reduction. From a survey conducted, practices related to overhead guide sign illumination and retroreflectivity in United States were summarized. A laboratory experiment was conducted to compare light distribution of five light sources: Metal Halide, Mercury Vapor, High Pressure Sodium, induction lighting, and Light Emitting Diode (LED). Cost analysis of the five light sources was performed. Combining results of the laboratory experiment and the cost analysis, induction lighting was recommended for states that want to continue external sign illumination. A retroreflectivity experiment was conducted to compare three types of retroreflective sheeting: Engineering Grade (type I), Diamond Grade (type XI), and High Intensity (type IV), to determine the sheeting that best increases visibility and legibility. Diamond Grade (type XI) was found to be the optimal sheeting that increases visibility and legibility to drivers during nighttime. A glare experiment was conducted to expand the retroreflectivity experiment results. Four sheeting-font combinations of High Intensity (type IV) and Diamond Grade (type XI) materials and Series E (Modified) and Clearview fonts were compared. Results revealed an optimal sheeting-font combination of Diamond Grade (type XI) sheeting and Clearview font which increases the visibility and legibility of guide signs to drivers under presence of oncoming glare source. The Highway Safety Information System (HSIS) database was used to study the effect of intersection lighting on the expected crash frequency. Illuminated intersections showed 3.61% and 6.54% decrease in the expected nighttime crash frequency as compared to dark intersections in Minnesota and California, respectively. In addition, partial lighting at intersections decreases the expected nighttime crash frequency by 4.72% compared to continuous lighting in Minnesota. The recommended sheeting-font combination for Departments of Transportation was Diamond Grade (type XI) and Clearview. This combination will increase signs’ visibility and legibility to drivers, and consequently increase safety on roadways. Adding partial lighting at intersections will reduce the expected nighttime crash frequency, and increase safety on roadways.

Quantitative, descriptive, cross-sectional study was conducted to determine the level of knowledge and extent of Computer Vision Syndrome (CVS) among computer users in the Securities and Exchange Commission (SEC), Abuja, Nigeria. Structured questionnaires were administered to 100 computer users aged between 18 and 40 years. The study findings revealed that 40 respondents (40%) were aware of CVS and 27 (27%) of them had knowledge of the disorder. 74 (74%) of the respondents experienced at least one symptom of CVS. Headache and eyestrain were the most common symptom of CVS among the population. The study also revealed that the internet (accounting for 50%) was the major source of information about CVS awareness. The study concluded that 27% knowledge level is too low and much emphasis is needed to educate the people at risk of CVS / Health Studies / M.A. (Public Health)