Les écrans dans la ville sont les nouveaux écrans d'affichage numériques exposés depuis le début des années 2000 dans les villes industrialisées. Les marches quotidiennes dans la ville révèlent qu’ils sont qualifiables d’écrans d’ambiance. Ils montrent un rapport d’iconicité avec les œuvres picturales, dont les mises en place dans l’espace s’apparentent à une mise en exposition muséale. Intégrés dans la dynamique de la vie citadine, ils se fondent dans le contexte de vie, où leurs esthétiques formulent un climat moral et affectif. Mais ces écrans d'expositions de l’image ne peuvent être étudiés comme de l’art, ni comme des éléments d’ambiance, car ils sont avant tout des médias de communication. Cette thèse pose la question de savoir comment les écrans dans la ville, disposés dans le décor de vie des citadins, assurent la fonction de communiquer un message. Le dispositif est tout d’abord défini selon une étude historique de son origine. Ensuite, une méthodologie d’analyse est construite d'après la classification d’un relevé photographique international, et les résultats d’un entretien basé sur l’activité d’un citadin. Elle est appliquée à une enquête de terrain par observation directe dans 14 types de lieux parisiens (institutions et entreprises ; postes et banques ; agences de télécommunications ; services de transport ; agences immobilières ; supermarchés ; boulangeries ; nouveaux commerces ; confiseries ; tabacs ; bars ; lieux culturels ; parvis ; restaurants). L’enquête montre en définitive, que la mise en exposition de l'écran et de son image consiste à être la mise en présence d’une communication, opérant comme un outil de valorisation de lieu. / Screens in the city are the new digital displays, they have been shown in industrialized cities since the beginning of the 2000s. As one walks through the city, they create a certain ambience. Digital display relate in an iconic manner to the images, whose displays in space seems to be like a museum exhibition. Incorporated into the dynamics of urban life, those screens merge with the context of living, where their aesthetics shape a moral and emotional atmosphere. But those digital displays cannot be studied as art, nor can they be studied as pure elements of ambience, because they are, first of all, a media of communication. This research seeks to find out how digital screens in the city, displayed in the life décor of the inhabitants, undertake the function of communicating a message. The apparatus of the screen is first defined following a historical study of its origin. Then, a method of analysis is constructed based on the classification of an international photographic transcript and the results of an interview of one inhabitant. This method is applied to a field study through direct observation within 14 Parisian spaces (institutions and firms; post-offices and banks; telecommunication agencies; transportation services; real estate agencies; supermarkets; bakeries; new shops; candy stores; tobacco shops; bars; cultural venues; forecourts; restaurants). The results of the inquiry show that the display of a screen consists of the exhibiting and materialization of a communication, operating as a tool for space valorization.

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.