En ögonamputation innebär en livslång begränsning av synfunktionen vilket kan förväntas påverka livskvaliteten. Syftet var att identifiera faktorer som påverkade livskvalitet på lång sikt efter en ögonamputation i vuxen ålder samt att beskriva hur livskvaliteten påverkades. Metod: Litteraturstudien följde niostegsmodellen av Polit och Beck (2017). Artiklarnas relevans bedömdes i tre urvalssteg: 1. Huruvida titel/ sammanfattningen matchade syftet. 2. Huruvida artiklarna i sin helhet matchade syftet samt in- och exklusionskriterierna. 3. Kvalitets­bedömning. Databearbetning: Faktorer som påverkade livskvalitet hos ögonamputerade protesbärare sorterades efter likheter och olikheter. Kategorier formulerades och tre karakteristiska teman identifierades bland dessa. Resultatet baserades på sju artiklar. Bland faktorerna som påverkade livskvalitet efter en ögonamputation identifierades tre teman ’Slutgiltig fysisk förändring’, ’Psykiska och känslomässiga påfrestningar’ samt ’Socialt undvikande beteende’. Temat ’Slutgiltig fysisk förändring’ tilldelades kategorierna ’Två blir ett: Enögdheten & monokulärt seende’ och ’Ett camouflerat operationsärr: Ögonhåla & protes’. ’Bearbetning av ögonförlusten’, ’Psykologiska problem’ samt ’Utmattning’ var de tre kategorierna tillhörande temat ’Psykiska och känslomässiga påfrestningar’. Temat ’Socialt undvikande beteende’ tillhörde kategorierna: ’Upplevd begränsad funktionsduglighet’ och ’Osäkerhet i mellanmänskliga relationer’. Slutsatsen: Studien sammanfattar kunskapsläget kring faktorer som påverkar livskvalitet efter en ögonamputation på lång sikt. Kunskap som behövs för att kunna optimera rehabiliteringsprocessen, ge god omvårdnad samt förhindra utanförskap. / Amputation of an eye results in life-long limitations of eye sight function which can be expected to affect quality of life (QoL). The aim of this study was to identify factors having long-term effects on QoL after amputation of an eye in adult patients and to describe in which way QoL was affected. Method: A litterature review following nine steps according to Polit and Beck (2017) was performed. Selection of relevant scientific articles was done in three steps: Evalutating relevance according to 1. title and abstract, 2. Article as a whole concidering aim of the review and criteria for in- and ex-clusion. 3. Study quality. Data analysis: Factors affecting QoL due to eye-amputation and wearing of an artificial eye were sorted according to similarities and differences. That way different categories were formed and among those main themes were identified. The result was based on seven articles. The three main themes that could be identified among factors influencing QoL after amputation of an eye were: ’Definitive physical changes’, ’Mental and emotional strains’ and ’Social avoidance’. Characteristic categories for the theme ’Definitive physical changes’ were ’Two become one: Monocularism & monocular sight’ and ’A camouflaged operation scar: Eye socket & prosthesis’. ’Processing the loss of an eye’, ’Psychological problems’ and ’Fatigue’ were three categories belonging to the theme ’Mental and emotional strains’.  The theme ’Social avoidance’ included categories like ’Experienced limited functioning’ and ’Uncertainty in interpersonal relationsships’. Conclusions: The review tries to sum up available ’recent’ research on factors with long-term effect on QoL after amputation of an eye. Knowledge which is necessary to improve rehabilitation- and caring-interventions as well as to prevent alienation in such patients

Die Kombination von Eyetracking und fMRI in den Neurowissenschaften ist eine relativ neue Methode, die einerseits eine technische Herauforderung darstellt, andererseits neue Möglichkeiten des Zugangs zu neuronalen Prozessen darbietet. In der vorliegenden Arbeit wurden durch Kombination beider Methoden Prozesse der neuronalen und visuellen Verarbeitung von Emotionen untersucht. Zunächst wurde die Rolle von verschiedenen Gehirnregionen innerhalb des emotionalen Netzwerks sowie die Frage nach der Lateralität der emotionalen Verarbeitung untersucht. Die Ergebnisse zeigten, dass die neuronale Antwort in den unterschiedlichen Regionen in erster Linie die Anforderungen an die jeweilige funktionelle Einheit spiegelt. Im Rahmen der Untersuchungen von visueller Verarbeitung wurden die einzelnen spezifischen Blickbewegungsmuster für Emotionen Angst, Ekel und Freude erstmals charakterisiert. Es wurden auch Habituationseffekte auf die beschriebenen Blickbewegungsmuster untersucht. Die gemeinsame Analyse beider Datensätze zeigte, dass zwischen visuellen und neuronalen Prozessen eine enge qualitative Interaktion besteht. Es wurde ein Zusammenhang zwischen der Betrachtungsdauer und der tiefe der Verarbeitung nachgewiesen.

Thesis (MPH.) -- University of Limpopo, 2021 / Dry eye disease (DED) is defined as a multifactorial disease of the tears and ocular surface that results in symptoms of discomfort, visual disturbance, and tear film instability with potential damage to the ocular surface. It is accompanied by increased osmolality of the tear film and inflammation of the ocular surface. DED is one of the most frequently established diagnoses in ophthalmology and represents a growing public health concern, with consequences that remain widely underestimated. There is variability of clinical manifestations and diagnostic criteria which leads to poor correlation between clinical signs and symptoms, therefore resulting in difficulties to assess prevalence of DED despite an improved understanding of pathogenic factors of acquired DED. However, its prevalence has been reported to range from 74% to 33% worldwide and the current study aimed to investigate the prevalence of DED and its determinants amongst people consulting at Focus Optometrists in Kwa-Mhlanga Township in Mpumalanga Province. Methodology: The current study was quantitative in nature and it followed a cross-sectional descriptive design to address the research question. The study population were people consulting at Focus Optometrists in Kwa-Mhlanga Township in Mpumalanga Province in which two standardized optometry diagnostic tests (Schimer test and the tear film break up time) were used for data collection coupled with a comprehensive case history which was taken for all participants. Data analysis was done using the STATA statistical software version 12 for Windows (STATA Corporation, College Station, Texas). Frequency tables were used to make comparisons between groups for continuous and categorical variables using student t-test, and chi-square test. P-value less than 0.05 at 95% confidence level were regarded as significant. Results: A total of 236 participants were recruited and the mean age of the participants was 39.7 in which majority of participants were females and there was a statistical significance difference in age groups of both males and females at p-value=0.011. Majority of the participants have reported to have experience of sensitivity to light vi and foreign body sensation sometimes. The poor vision and blurred vision have been reported by majority of participants sometimes and the prevalence of dry eye disease was found to be 80.9% and the risk of the dry eye disease in the current study was found significantly increasing with old age. Those who were older (35 years above) were 4.2 times more likely to develop dry eye disease at p-value <0.001 as compared to young participants. Female gender was found not to be protective of developing dry eye disease in the current and participants who were single, having secondary and education qualifications were more likely to develop dry eye disease. Participants with ocular conditions, systemic disease, surgery and those with high blood pressure were more likely to develop dry disease Conclusion: The prevalence of dry eye disease in the current study was found to be very high and therefore, patients coming to the clinic from the age of 40 with underlying systemic diseases should be screened for dry eyes. Dry eye disease can be a major contributor of refractive error in the visual systems and or can also be a sign or a symptom of hormonal or related ocular or systemic disease. More eye care awareness should be done at primary eye care level to detect the cause or to eliminate future associated symptoms.

This thesis is a systematic investigation of preparatory reorienting of task-relevant spatial attention. Task switching experiments typically report a performance overhead when the current task is different to that performed on the previous trial relative to when the task repeats. This ‘switch cost’ tends to reduce as participants are given more time to prepare (consistent with an active reconfiguration process) but a ‘residual’ switch cost usually remains even at very long preparation intervals (often interpreted as evidence of carryover of response selection parameters from the previous trial which are immune to preparation). Although attentional selection of perceptual attributes is often considered to be part of task-set and is included in some models of task-set control, little research has investigated the dynamics of this component in detail. Over a series of seven experiments in which tasks were consistently mapped to screen locations, eye-tracking was used to systematically investigate task-relevant spatial selection of perceptual attributes during the preparation interval and early after stimulus onset. Experiment 1 revealed a switch-induced delay in appropriate attention orientation and a measure of ‘attentional inertia’ which could not be explained by task-independent re-orienting to locations or low-level oculomotor phenomena but were markers of task-relevant spatial selection. Experiment 2 provided a sensitive measure of both of these attentional handicaps and demonstrated that they both contribute to the switch cost (including its residual component). Although attentional inertia reduced with preparation, both handicaps were present at the longest preparation intervals. The constancy of the delay in attending to the relevant attribute reflects the effort to re-allocate attention, rather than peculiarities of spatial orienting when the cue and stimulus are presented near-simultaneously on trials with short cue-stimulus intervals. The presence of attentional inertia in blocks with long preparation intervals suggested some component of inertia immune to preparation (though see Experiments 5 and 6 below). Experiments 3 and 4 investigated the extent to which attentional selection can be decoupled from other task-set components. Cues which explicitly provided location information reduced (or eliminated) the attentional effects found in Experiment 2 indicating that attentional selection can be decoupled from other task-set components. However, Experiment 3 found that the ‘natural’ state is for attentional selection to be coupled at least to a degree (and accessed via) task-set. Experiment 5 combined eye-tracking with ERPs to investigate the relative order of attentional selection and reconfiguration of other task-set components. A well-documented ERP marker of task-set preparation always followed onset of the first fixation on the currently relevant stimulus element indicating that (at least some) task-set components are reconfigured in a serial order with spatial selection preceding other components (e.g., loading of S-R rules or other parameters into working memory). Experiments 6 and 7 investigated the nature of attentional inertia. In Experiment 6 participants were given ultimate control over the duration of the preparation interval which eliminated attentional inertia (at least as indexed by preferential fixation of the previously relevant element on switch trials). In Experiment 7 the stimulus comprised three items which were from perceptually distinct classes (digits, letters, objects) to investigate whether the presence of task-specific features would elicit extra attentional inertia and whether early spatial selection was effective enough to block the processing of task-irrelevant features once the stimulus was presented. Although there was some evidence that the previously relevant stimulus element ‘captured’ attention, this tendency was modest in the fixations and absent in performance measures (response congruence effects).

The early detection of acquired losses of colour vision can provide the ophthalmologist with a very sensitive indicator of visual dysfunction. As a result we have developed and tested an automated, CRT-based, chromatic discrimination system that allows us to measure acquired colour-vision deficits with great precision. This system, known as the Sussex Gratings Machine, can produce chromatic stimuli in any direction in equal luminance colour space. However, we have found that measurements made along a constant MIL-cone axis (Tritan) or a constant S-cone (Red/Green) confusion axis are most useful. Using this system we have investigated acquired colour vision deficits in diabetes ,. and thyroid eye disease. We have shown that tritan discrimination losses can be used to screen for severe diabetic retinopathy and also to predict those who are likely to develop it within 18 months. We have also confirmed that acquired tritan discrimination losses are a very useful indicator of optic-nerve compression in thyroid eye disease.

The mantis shrimp Gonodactylus oerstedii is known to possess eyes capable of colour and polarised light vision. The apposition compound eyes of these creatures are highly mobile and their ommatidia are specialised to analyse the spectral and e-vector qualities of light in a central strip of the eye called the midband. The retina of the midband of Rows 1-4 is tiered with each row being sensitive to a narrow region of the colour spectrum. Row 5 and 6 ommatidia possess many structural features designed to allow the e-vector direction of light to be detected. This thesis investigates the neuroanatomy in the neuropile regions below the retina in an attempt to elucidate the mechanisms which allow colour and polarised light vision to take place. In Chapter 2 the retina-lamina projection of the retinal axons is studied in an ommatidium in Row 3 of the midband, and the findings suggest that the stomatopod is similar to all other crustacea so far studied, despite its unusual retina. Chapter 3 investigates the neuroanatomy of the medulla neuropile regions. A novel region of the medulla externa which deals with colour information is discovered. In Chapter 4 the lamina of Rows 1-4 is looked at in more detail, with the number of monopolar cells and the detailed arrangements of the retinular cell terminals being ascertained. The terminals sensitive to different regions of the spectrum are located in different areas of the lamina cartridge. Chapter 5 looks at many of the issues above but this time in relation to rows 5 and 6 of the midband, which are specialised for polarisation vision. The lamina neuropile is very different to that of Rows 1-4 and again a specialised region of the medulla externa is found which processes information from these rows. This thesis provides evidence that the optic lobes of Gonodactylus oerstedii are comparable to other crustacea but nevertheless may possess some intriguing specialisations related to their extraordinary colour and polarised light vision.

Relational memory refers to memory for arbitrary associations among components of experience, and is thought to be critically dependent on the hippocampus. Previous studies suggested that age-related differences in relational memory were consistent with a protracted developmental trajectory of hippocampus. Recently, eye tracking studies conducted in infants have concluded that eye movement detection could provide one indirect index of relational memory and hippocampal function in infants as young as 6 months. While the eye-based memory expression has been detected in adults on relational memory tasks, this effect has been less studied across development, and the few studies that have been conducted have suggested discontinuity in eye-movement behaviors across age. The purpose of the current study is to examine the development of relational memory in middle childhood (7-8 years of age) by utilizing a face-scene binding paradigm. Behavioral results revealed that adults showed higher identification accuracy than children when recalling matching faces based on scene cues. The eye movement data indicated that adults showed stronger and more rapid looking preference to matching face during correct test trials, and the proportion of viewing time towards matching face was significantly greater than children on incorrect trials (while performance was below chance in both age groups). Therefore, eye movements do index relational memory and correct responses but show rapid onset only in adults. We discuss these results in the context of the neural systems that may support eye movement behavior across the lifespan and conclude that more work is required to determine the nature and strength of these effects prior to adopting eye-movements as a continuous measure of relational memory across development.

published_or_final_version / abstract / Medicine / Doctoral / Doctor of Philosophy

published_or_final_version / Nursing Studies / Master / Master of Nursing

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