Syfte: Syftet med denna studie var att undersöka om ett kortare synavstånd till smartphone resulterar i mer ögonrelaterade symtom. Metod: Deltagarna var slumpmässigt tillfrågade mellan åldrarna 19 och 37 år. Deltagarna (n=63) fick svara på symtomenkäten Convergence insufficience symptom survey (CISS) gällande närseende och läsning. Under tiden mättes synavståndet mellan deltagarnas ögon och smartphone. Symtomenkäten var webbaserad och deltagarna svarade med sin smartphone. Höjden på versalen [H] mättes och tillsammans med synavståndet räknades synvinkeln ut. Resultat: 76% av deltagarna var kvinnor, 22% var män och 2% saknade könstillhörighet. Deltagarnas medelålder var 24 år. Studien indikerade inte på ett statistiskt signifikant samband (r=0,219, p=0,102) mellan CISS-poäng och synavstånd till smartphone. Däremot indikerades en svag korrelation mellan de två variablerna. Resultatet visade även att endast 2 deltagare i studien hade en mindre synvinkel än 16 bågminuter. Slutsats: Denna studie fann inget statistiskt signifikant samband mellan synavstånd till smartphone och astenopiska besvär. Däremot påvisar studien en svag korrelation mellan synavstånd till smartphone och astenopiska besvär.

The 2010 National Education Technology Plan steadily replaces paper textbooks with study materials on computers. One risk of increased computer usage is increased Computer Vision Syndrome (CVS) symptoms. I researched multiple studies to analyze the effects of computer use on dry eye and eye strain and how these symptoms can progress to musculoskeletal pain, headaches, decreased quality of life, loss of confidence and even anxiety and depression. Currently, there is not much data on tablet use so I propose two future experiments to determine if tablets can also cause CVS ocular symptoms.

Les simulateurs sont de plus en plus intégrés dans le milieu industriel car ils facilitent les processus de fabrication et de test des objets. Dans ces simulateurs, comme dans d’autres domaines d’application de la réalité virtuelle, des écrans stéréoscopiques sont utilisés afin de rapprocher la vision sur écran de la vision naturelle. Toutefois, l’ajout de la stéréoscopie pose des problèmes au niveau physiologique, comme le conflit vergence-accommodation. Ce conflit est une des causes majeures de fatigue visuelle en vision stéréoscopique.Dans une première partie nous allons nous intéresser aux différentes méthodes permettant de réduire les effets du conflit vergence-accommodation. Puis, nous proposerons, expérimenterons et validerons un nouveau traitement : l’ajout d’un flou en vision périphérique. Ce traitement nous a permis de réduire la fatigue visuelle. Nous avons de plus trouvé que plus la zone nette est petite, plus le traitement est efficace.La deuxième partie de ce manuscrit sera consacrée à l’amélioration de la perception des formes en vision stéréoscopique artificielle. L’apport principal sera la prise en compte du point de regard dans le processus de rendu afin de reproduire l’impact de la direction du regard sur la perception de l’environnement et ainsi améliorer la perception de l’environnement virtuel. Cela génère des parallaxes verticales en vision périphérique. Cette nouvelle méthode de rendu permet d’améliorer la perception des formes lorsque celles-ci sont proches de l’utilisateur. / Simulators are more and more used in industry because they help for making and testing objects. Like in other domains, simulators use stereoscopic screen to get closer natural vision and artificial vision. However, stereoscopy create some physiological problems like vergence-accommodation conflict. This conflict is one of the main cause of visual strain while viewing stereoscopic contents. In a first part, we will see some methods to reduce visual fatigue due to vergence-accommodation conflict. Then, we will propose, test and validate a new method: a blur in peripheral vision. This treatment reduce eye strain. In addition, we found out that the smaller the sharp area is, the more effective the treatment is. In the second part, we will focus on the shape perception in stereoscopic vision and how to improve it. The main contribution will be to take into account the user’s gaze point in the rendering process to reproduce the effect of the gaze direction in natural vision and improve the perception of the virtual environment. This camera convergence create deformations – called vertical parallaxes – on the screen in peripheral vision. This new method improve shape perception if objects are located close to the user.

Accommodative microfluctuations (AMFs) are temporal variations in the accommodative response. AMFs can be divided into two categories, the low frequency component (LFC) measuring below 0.6 Hz and the high frequency component (HFC) measuring between 1.0 and 2.3 Hz. This thesis examined occupational factors that may affect AMFs comprising of cognitive demand, visual fatigue and the type of digital display used. These effects were measured by assessing changes in the LFC, mid frequency component (MFC), HFC, and RMS accommodation. Analysis of chaos and the overall accommodative response (AR) was also used. Furthermore, an investigation into inter- and intra-participant variability was completed. The HFC was shown to increase in line with increasing cognitive demand. A significant effect for task duration was found at higher accommodative demands for the overall AR, LFC and MFC. There was a significant effect on the LFC and AR depending on the type of display used during near work. The HFC and MFC were found to be less repeatable in the same participant relative to LFC, RMS accommodation and AR measurements. AMFs appear to have an effect on occupational factors, however more research is required to assess how much of an effect they may have relative to other ocular factors that affect occupational settings.

Syfte: Syftet med den här studien var att jämföra Digital Eye Strain-symptom mellan läsning på papper och mobiltelefon. Att undersöka om det som tidigare studier har visat i skillnad mellan läsning på papper och en datorskärm även gäller mobiltelefoner och hur mycket våra ögon påverkas när det gäller ansträngning, trötthet och andra ögonrelaterade symptom.  Metod: Deltagarna (n=16) fick läsa i 20 minuter tyst, antingen på papper eller en smartphone-skärm. Avståndet fick de själva bestämma. De läste samma bok med samma typsnitt och storlek på båda medierna. Direkt efter de hade läst i 20 minuter fick de fylla i ett frågeformulär som bestod av tio frågor kring deras upplevda ögonsymptom under uppgiften. Resultat: Studien visade på signifikanta skillnader i medelvärdet mellan papper och mobiltelefon på tre av symptomen: suddig syn vid tittande på texten (p=0,016), ansträngda ögon (p=0,023) samt trötta ögon (p=0,015). I alla tre fallen var symptompoängen högre efter läsning på mobilskärm än efter läsning på papper. Det fanns ingen signifikant skillnad mellan de övriga sju symptomen. Det var även en signifikant skillnad i läsavstånd med ett betydligt mindre avstånd till mobiltelefonen än till pappret. Slutsats: Studien visar att symptomen efter användning av mobiltelefon upplevs som svårare än efter läsning på papper. De tre symptom som skilde sig signifikant var alla högre efter läsning på mobilskärmen. / Purpose: The purpose of this study was to compare Digital Eye Strain DES-symptoms after reading on a printed hardcopy versus a smartphone. To understand if results obtained from earlier studies that have showed DES when reading in from computer also applies to smartphones. Methods: 16 participants in the study were asked to read a Swedish book quietly for 20 minutes, either on a hardcopy or on a smartphone. The participants were told to use their normal working distance while reading from book or smartphone. They read the same book with the same textsize and font in both conditions. Directly after reading the participants completed a written questionnaire that consisted of ten questions about their level of ocular discomfort during the task.   Results: This study showed significant differences in mean symptom scores between printed hardcopy and smartphone on three of the symptoms; blurred vision while viewing the text (p=0,016), eyestrain (0,023) and tired eyes (0,015). In all three cases the symptoms were higher during smartphone use. No significant differences were found between the other seven symptoms. There were a significant difference in reading distance, smartphone were held closer than the hardcopy. Conclusion: This study shows that the symptoms after smartphone use is perceived as more severe than after reading on a hardcopy. The three symptoms that showed a significant difference were all higher after smartphone use.

Purpose – As screen time per individual increases, more users of digital devices experience ocular related diseases. The purpose of this study is to gather reasons for the vast popularity Dark Mode gained in contemporary society, by investigating previous design eras. As a general lack of trend analysis within user interface design has been identified, the goal of the study is to lay the foundation for further research in the field of user interface design. Method – The study relies on a qualitative literature review. Publications related to Dark Mode, light-on-dark color schemes and digital trends were analyzed for topic-specific content that was then elaborated to give a critically viewed framework of the emerging trend. Findings – The results of our study indicate that various factors led to creation of the hyped trend, known as Dark Mode. It was first and foremost practicality of the light-on-dark color scheme that paved the way for Dark Mode. All operating systems, many apps, platforms and even websites incorporated it in their design. Being an optional feature, Dark Mode makes it more comfortable for users to use their devices outside the light hours or in environments with bad lighting conditions. With Dark Mode users get a far-reaching personalization tool, that visually changes essentially the whole OS or app. From a psychological point of view this improves user satisfaction, as humans naturally are seeking way to be in control. Being in control of own devices is undoubtedly an important aspect of it. Besides that, Dark Mode houses potential to lower energy consumption of devices and provides users with longer battery times. This, however, only applies to devices with display technology like OLED, where backlighting is at least divided into zones, that can be turned off when not in use. Devices with conventional LED displays cannot benefit from lower energy consumption. Implications – The study indicates that individuals use Dark Mode for a more satisfying user experience as they feel e.g. less eye strain with a dark themed user interface. Editing and coding software is mostly designed in a light-on-dark color scheme, as users often work for long continuous hours on screen, surrounded by dark environment. As screen time per individual increases, more users are experiencing ocular diseases. In counteraction, society demanded dark themed interfaces for operating systems, websites, and apps. As individuals were already using unofficial dark themes on different interfaces, tech companies started releasing system updates to make Dark Mode a choice. As Apple released their user interface update just in 2019, Dark Mode is still a relevant trend discussed in the industry and society. Experts indicate that Dark Mode is here to stay, as it satisfies preferences of many users and makes current OLED screens and future digital devices with appropriate display technology more sustainable. Limitations – The time frame of the study, as well as the Covid-19 pandemic greatly limited the possibilities of conducting the study. Due to the novelty of the trend, there is lack of previous research, which limited the view on the subject to only work available. Keywords – Dark Mode, dark-on-light color scheme, retro trends, user interface design, user experience, digital trends, display, screen, screen time, eye strain

I prepared my thesis on Health Support at Workplaces under Particular Conditions of a Textile Factory. The main objective was to determine the company management?s activities in the field of health support. The second objective was to map the information provided to the staff on health support at the workplace, and the third objective was to propose the concept of a specific preventive programme. When preparing the concept of the preventive programme for the textile company I co-operated with the company management and with the company doctor. The reference group was represented by women employed in a textile plant in South Bohemia who worked in different workshops producing car seat covers, housing and children?s clothing. The work described in this thesis was carried out as quantitative research. For data collection I used anonymous questionnaires and the results of this research were plotted on graphs. The thesis is divided into a theoretical part and an empirical part. The theoretical part mainly deals with health support at the workplace, with an analysis of health risks at work including the impact of physical factors. At the beginning of the empirical part I set the goals and set out three hypotheses. Having analysed the collected data I found that H1, H2 and H3 were confirmed. The empirical section includes a description of the research technique which shows that more than 50 per cent of employees of the textile factory are overweight, then that there is a greater occurrence of health problems in the departments of sewing and embroidery machines and many women also had no idea of the meaning of health support at the workplace. According to the results it is possible to say that the textile company does not organize any physical activities or rehabilitative exercises for their employees. Based on the information I would recommend organizing sports courses, providing healthy canteen meals, reducing stress at the workplace and introducing dust extractors in order to reduce dust at the workplace. This thesis may bring the company better working comfort and help to improve the employees? health. The proposed preventive programme can also be a manual for employers in the textile plant in the field of health support at the workplace.