Dissertation/Thesis Abstract

Die Verteilung von Aufmerksamkeit bei zentralem Sehverlust
by Wienrich, Carolin, Dr.Nat., Technische Universitaet Berlin (Germany), 2015, 290; 10701418
Abstract (Summary)

Age-related Macular Degeneration (AMD) is a retinal disease causing the progressive loss of macular vision. Initially, central vision seems like a light haze (blurred vision), which gradually becomes more and more dense. Later on, the central scotoma is entirely evolved (central vision loss), confining the patient to rely solely on peripheral vision to achieve visual tasks. The main aim of the present thesis is to investigate visual attention in adaptation to central vision loss progress. The topic might be examined from two points of view: From an applied point of view, one could ask: How does a central vision loss impact visual attention? In order to investigate this impact, different experimental paradigms might be performed with AMD patients and corresponding controls. From a more scientific point of view, one could ask: What could we learn about the interrelationship between visual acuity and visual attentional in the presence of a central vision loss? Whereas the approach in the first case reveals a descriptive character, the second case implies a theory-driven approach. At the last-mentioned approach, the central vision loss initially serves as research method, before it becomes the subject of research. This thesis focuses on the second approach. It's been systematically examined how factors of the disease itself (scotom opacity) as well as more objective parameters of the task (stimulus contrast, item size) determine the visual search. In order to model the interrelationship between the attentional focus size and visual acuity, two hypotheses were contrasted (Gradientenhypothese versus Fixationsorthypothese). In the first part of the present thesis, the following research questions were answered: How do retinal acuity and the visual attention interrelate? Does the attentional focus size depend upon the fixation point on the retina? In order to answer these two questions, the central vision loss serves as research method in the form of gaze contingent simulated scotomata. The main result of Experiment 1 revealed constant large attentional focus sizes in participants with opaque simulated scotomata. Experiment 2 underlined the results of Experiment 1, even though, no eye movements were possible. Oculomotor irritation could be excluded. The second part answered the following questions: How do AMD patients allocate their visual attention? Does this allocation depend on the progress of their central vision loss (impact of scotom opacity)? At this point, the central vision loss becomes the subject of research. In Experiment 3 and 4, the visual search behavior of AMD patients with central scotomata corresponded with simulations investigated in Experiment 1 and 2. While individual patients differed from the expectations, the results were in line with the Gradientenhypothese.

Indexing (document details)
Advisor: Müller-Plath, Gisela
School: Technische Universitaet Berlin (Germany)
School Location: Germany
Source: DAI-C 81/1(E), Dissertation Abstracts International
Subjects: Biomedical engineering, Neurosciences, Ophthalmology
Keywords: Vision loss
Publication Number: 10701418
ISBN: 9781392605530
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