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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
281

Eye preference in humans and its correlation with eye dominance, visual acuity and handedness

Cederlund, Joakim January 2016 (has links)
Handedness is the most obvious expression of lateralized behaviour in humans. However, there is only limited knowledge about other forms of lateralized behaviour, e.g. preferential use of an eye and whether these may correlate with handedness. Thus to investigate this, 100 subjects (50 males and 50 females) between 11 and 80 years of age were assessed for their eye preference, eye dominance, visual acuity, and handedness. Eye preference was assessed by performing four different monocular tasks, eye dominance by performing the binocular Dolman test, visual acuity was assessed with a Snellen chart and handedness was surveyed using the Edinburgh Handedness Inventory. Regarding eye preference, the right eye was preferred by 69% of the subjects. 90 % of the subjects were consistent for their preferred eye across all four tasks. 66% of the subjects had a dominant right eye, 33% had left eye dominance and 1% could not be assessed using the Dolman test. 56% of the subjects differed in their visual acuity between both eyes, while 43% had the same visual acuity in both of their eyes. 86% of the subjects were right-handed while 4% were left handed and 10% were ambidextrous. Significant correlations were found between visual acuity and eye preference and between visual acuity and eye dominance. The study also found a positive correlation between handedness and eye preference. These results support the notion that there is a weak correlation between the different aspects of lateralized behaviour in humans.
282

Zum zeitlichen Zusammenhang zwischen der Verschiebung der selektiven visuellen Aufmerksamkeit und den Bewegungen der Augen

Hofmann, Mathias 26 August 2013 (has links) (PDF)
Was wird zuerst verlagert und was folgt hinterher? Bei der Betrachtung der menschlichen Wahrnehmung spielen die Verlagerung des Orts der visuellen Aufmerksamkeit und die Verlagerung des Fixationsorts eine wichtige Rolle. Zur Reihenfolge, in der beide verlagert werden, existieren unterschiedliche Annahmen und Forschungsergebnisse, die vorgestellt werden. Es werden zwei zu dieser Thematik durchgeführte Experimente berichtet, in denen versucht wurde, vorliegende widersprüchliche Forschungsergebnisse zu integrieren. Es sollte gezeigt werden, dass neben der Aufmerksamkeit weitere Einflussgrößen existieren, die in Hinsicht auf diese Widersprüche Erklärungskraft besitzen. Mittels Bildbetrachtung und darauf folgender Wiedererkennensaufgaben wurde bestätigt, dass zu Beginn einer Fixation häufiger Ort und Inhalt der vorangegangenen Fixation angegeben werden. Dies wird nicht als ein Hinterherhinken der Aufmerksamkeit, sondern als Indiz für eine verzögerte Verarbeitung der Fixationsinhalte interpretiert. Im zweiten Experiment wurde zudem gezeigt, dass es kaum möglich ist, den Inhalt spezifischer vergangener Fixationen – hier konkret der vorletzten – gezielt zu erinnern.
283

Opthalmic Use Of Sodium Cephalothin: An In Vivo Comparison

Carney, Gerald R. 08 1900 (has links)
A rabbit keratoconjunctivities model was used to evaluate ophthalmic formulations containing 1 percent sodium cephalothin in silicon oil, a 1 percent sodium cephalothin aqueous solution, and a 0.3 percent gentamicin sulfate solution. Rabit eyes were inoculated intracorneally with Pseudomonas aeruginosa, Staphylococcus aureus, or Streptococcus pneumoniae, After topical treatment, none of the antibiotic formulations were effective in the P. aeruginosa model; all three showed good activity against S. aureus, and against S. pneumoniae, the caphalothin formulations were more effective than gentamicin.In a related stability study, the cephalothin potency of the silicon formulation was maintained for 16 weeks at 4, 25, and 450 C These studies suggest that sodium cephalothin can be formulated as an effective and stable ophthalmic dosage form.
284

Determinants of pterygium occurrence and recurrence in a rural African population

Anguria, Peter 16 September 2015 (has links)
A Thesis submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy / Pterygium, a wing-shaped fibrovascular growth of the conjunctiva onto the cornea, can impair vision and be cosmetically unacceptable. Its frequency varies in Africa and postsurgical recurrence in blacks may be high. Determinants of pterygium occurrence and recurrence in rural Africans are not known. This study aimed to establish the determinants of pterygium occurrence and recurrence in rural blacks. The case controlled study comprised 230 patients and 157 controls. Interviews and eye examination were conducted; however, data from 150 patients and 150 controls were analyzed as pre-calculated. Families of 51 cases and 50 controls were studied. Surgery was done on 200 eligible patients. Those who experienced post-surgical recurrence were subclassified as cases and those who did not, controls. Immunohistochemistry was done on 59 pterygium sections and 7 controls. Family history of pterygium was present in 46 cases (30.6%) of 150, and 15 controls (10%) of 150; Odds ratio (OR) =3.93; p <0.01. Traditional eye medication was used by 79 cases (52.6%) of 150, and 60 controls (40%) of 150; OR =2.03; p <0.01. The tear film was unstable in 10 cases (6.6%) of 150, and 26 controls (17.3%) of 150; OR =0.30; p <0.01. Groups of 3-5 individuals per household were pterygium-affected in 36 pterygium families (70.5%) of 51 vs. 1 control (2%) of 50. After surgery, only 190 patients completed followup for a minimum duration of 6 months, and 52 (27.4%) experienced post-surgical recurrence. Of the 52 cases, 21 (40%) had grade 2 pterygia v. 8 post-surgical controls having grade 2 pterygia (6%) of 138; OR =9.1; p <0.01. The limbal basal epithelium expressed p53 in 11 pterygia (18.6%) of 59 v. 5 controls (71.4%) of 7; p <0.01. It expressed matrixmetalloproteinase-1 (MMP1) in 14 pterygia (23.7%) of 59 v. 5 controls (71.4%) of 7; p =0.02. MMP2 and MMP3 were detected in 16 cases (27.1%) of 59 v. 5 controls (71.4%) of 7; p =0.03. Pterygium occurred in families and was associated with traditional eye medication. Pterygium occurrence was not associated with unstable tear film, p53, and MMPs. Postsurgical recurrence was connected to grade 2 pterygia.
285

L’hypertexte et la lecture à l’écran : approches expérimentale et herméneutique / Hypertext and reading the screen : approaches experimental and hermeneutics

Koszowska-Nowakowska, Paulina 10 July 2013 (has links)
Notre recherche a pour but de mettre à l’épreuve nos manières de lire à l’écran, afin d’amorcer une nouvelle réflexion sur la lecture hypertextuelle et son traitement informatisé. Lire à l’écran d’un ordinateur, signifie de saisir un objet textuel et visuel très complexe. Nous avons choisi d’étudier la perception, la structure et la construction de la lecture hypertextuelle non-linéaire à l’aide d’un outil oculométrique, appelé Eye-Tracking. Dans cette exploration, nous passons de la perception visuelle humaine à la construction du sens. A partir de nos préoccupations de départ concernant les relations entre l’intertextualité et l’hypertexte, nous cherchons à savoir comment le lecteur d’un hypertexte construit sa lecture ; est-ce qu'il trouve de la linéarité dans cette lecture fragmentaire ?Cette thèse se situe au croisement de plusieurs disciplines scientifiques, tels que la sémiotique et l’oculométrie, tout en restant ancrée dans les Sciences de l'Information et de la Communication, c’est pourquoi nos mesures d’Eye-Tracking nécessitent plusieurs phases de traitement des données. Ce travail porte sur le regard, mais aussi sur le comportement humain, c'est pour cela que nous tentons à décrire au même temps les processus perceptifs et cognitifs observés.L’objectif de notre recherche est aussi de démontrer qu’un texte numérique est à l’origine du changement des rapports : auteur, texte, lecteur , où la notion de contexte et de l’intertextualité changent la dimension. Ce travail s’inscrit dans la continuité de travaux menés dans le domaine de l’hypertexte (Jean Clément, George Landow, Olivier Ertzscheid, Luc Dall’Armellina, Christian Vandendorpe, Jean-Pierre Balpe, Serge Bouchardon, Raja Fenniche, etc.), mais son originalité constitue la partie expérimentale réalisée avec le dispositif Eye-Tracking. / Our research intended to test the way we read on the screen, to initiate new thinking about reading hypertext and computer processing. Read the computer screen, means to grasp an object very complex textual and visual. We chose to study perception, structure and construction of hypertextual reading non-linear with an eye-tracking tool, called Eye-Tracking. In this exploration, we move from the human visual perception to the construction of meaning. From starting our concerns regarding the relationship between intertextuality and hypertext, we want to know how the reader constructs a hypertext reading, is that it is the linearity in this fragmentary reading? This thesis lies stands at the crossroads of several disciplines, such as semiotics and eye tracking, while remaining rooted in Information Science and Communication, which is why our measures Eye-Tracking require several phases data processing. This work focuses on the eyes, but also human behavior, that is why we are trying to describe at the same time the perceptual and cognitive processes observed.The purpose of our research is to demonstrate that digital text is the source of change reports: author, text, reader, where the notion of context and intertextuality change the dimension. This work is a continuation of work in the field of hypertext (Jean Clement, George Landow, Olivier Ertzscheid, Luc Dall'Armellina Christian Vandendorpe, Jean-Pierre Balpe, Serge Bouchardon Raja Fenniche, etc.). but his originality is made with the experimental device Eye-Tracking.
286

Quiet Eye Training and the Focus of Visual Attention in Golf Putting

January 2019 (has links)
abstract: Previous research has shown that training visual attention can improve golf putting performance. A technique called the Quiet Eye focuses on increasing a player’s length of fixation between the ball and the hole. When putting, the final fixation is made on the ball before executing the stroke leaving players to rely on their memory of the hole’s distance and location. The present study aimed to test the effectiveness of Quiet Eye training for final fixation on the hole. Twelve Arizona State University (ASU) students with minimal golf experience putted while wearing eye tracking glasses under the following conditions: from three feet with final fixation on the ball, from six feet with final fixation on the ball, from three feet with final fixation on the hole and from six feet with final fixation on the hole. Participant’s performance was measured before training, following quiet eye training, and under simulated pressure conditions. Putting performance was not significantly affected by final fixation for all conditions. The number of total putts made was significantly greater when putting from three feet for all conditions. Future research should test the effects of this training with expert golfers whose processes are more automatic compared to novices and can afford to look at the hole while putting. / Dissertation/Thesis / Masters Thesis Human Systems Engineering 2019
287

Utilization of public eye care services by the rural population of Capricorn District, Limpopo Province, South Africa

Ntsoane, Mologadi Dimakatso January 2010 (has links)
Thesis (MPH.) --University of Limpopo, 2010 / The Department of health, Limpopo province in recent years has developed eye care services in public hospitals. It is reckoned that people living in the rural areas would benefit significantly from the cheaper public eye care services. However, the level of utilization of the public eye care services by the rural communities in the province has not been investigated. It was therefore, considered of interest to evaluate whether or not the services are being utilized adequately or not. AIM OF THE STUDY The aim of this study was to investigate whether or not the public eye care services in the Capricorn district, Limpopo Province are adequately utilized by the rural population. METHODOLOGY A cross-sectional qualitative survey study design was used. A questionnaire with 42 questions on the utilization of eye care services was developed in English, translated to Northern Sotho (the local dialect) and back translated to ensure veracity. The questionnaire included questions on demography, knowledge of available eye care services, need for eye care services, utilization, attitude and perception of public eye care services. The questionnaire was field-tested in a pilot study conducted prior to the study and involves 20 participants, with final amendments made to ensure clarity of contents. The participants included males and females from 1000 households in selected 38 villages. The questionnaire was delivered to the head of each household for completion. Data analysis was done with computer software SPSS (Statistical Package for Social Sciences) version 15. Results are presented in narrative and tabular forms and as figures.
288

A state machine representation of pilot eye movements

Harris, Artistee Shayna 01 July 2009 (has links)
With the development of these new interfaces, such as Next Generation Air Transportation System (NextGen), and the evolution of the United States National Air System (NAS) from a ground-based system of Air Traffic Control (ATC) to a satellite-based system of air traffic management (FAA, 2009), new evaluations for efficiency and safety are required. Therefore, these tasks require visual behaviors such as search, fixation, tracking, and grouping. Therefore, designing and implementing a virtual eye movement application that generates gaze and action visualizations could provide detailed data on the allocation of visual attention across interface entities.The goal is to develop state-machine representations of straight-and-level flight, turns, climbs and descents within the Pilot Eye Flight Deck Application to simulate pilots' eye movement.
289

From vision to drawn metaphor : an artistic investigation into the relationship between eye-tracking and drawing

Baker, Catherine January 2012 (has links)
At its most essential drawing consists of the making of marks on a surface, however such an interpretation does not necessarily reflect the diverse practice of artists whose work seeks to challenge the conventions of drawing and establish new boundaries. This abstract documents a practice involving a new consideration for drawing which focuses on the active process of drawing as a physical and perceptual encounter. It proposes that eye movements and their associated cognitive processing can be considered as a drawing generating process. It does not seek to undermine the conventional three-way process of drawing involving eye, hand and brain but presents ideas which push against the established boundaries for drawing practice and has investigated new ways of making and new ways of considering the practice of drawing as a phenomenological contemplation. The proposition for drawing presented in this document, has been developed through a practice-led enquiry over the last eight years and involves using scientific methodologies found within the area of Active Vision. By examining artworks produced within the early part of the period of time defined within this thesis, emergent ideas relating to the act of making in-situ drawings and the recollection of such experiences brought about a series of questions regarding the process of generating a drawing. As the practice developed, using data obtained from different eye-tracking experiments, the author has explored the possibilities for drawing through using scientific methods of tracking the act of looking to investigate the relationship between the observer and the observer entity. Using the relationship between the drawn mark and visual responses to it as the basis for a practice-led period of research, this thesis presents the notion that by using technologies designed for other disciplines artists can explore the potential for drawing beyond the conventions cited above. Through the use of eye-tracking data the artist and author seeks to firmly establish the use of this scientific methodology within an artistic framework. It is a framework that responds to new ways of thinking about spatiality and the relations between sight and thought, taking into account the value of experience within the production of art; how the physical act itself becomes the manifestation of a process of drawing, understanding and knowledge of the world around us.
290

RESILIENCE AND ATTENTIONAL BIASES: WHAT YOU SEE MAY BE WHAT YOU GET

Valcheff, Danielle 17 March 2014 (has links)
Research suggests that, during stress, resilient individuals use positive emotion regulation strategies and experience a greater number of positive emotions than those who are less resilient. Therefore, differences could be expected in attentional biases towards emotional stimuli based on resilience. The current study investigated attentional biases towards neutral, negative and positive images in response to varying levels of resilence and mood induction conditions (neutral, negative and positive). Sixty participants viewed a series of pre and post-mood induction slides in order to measure attentional biases to emotional stimuli. The study provided evidence for the presence of trait and state congruent attentional biases. More resilient individuals demonstrated an initial bias towards positive stimuli and once emotion was aroused, the bias was away from negative stimuli. Additionally, mood congruent attentional biases were observed for participants induced into positive and negative mood states. Implications as they apply to research and clinical practice are discussed.

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