Some aspects of visual discomfort
Abstract
Visual discomfort is the adverse sensations, such as headaches and eyestrain,
encountered on viewing certain stimuli. These sensations can arise under certain
viewing conditions, such as stereoscopic viewing and prolonged reading
of text patterns. Also, discomfort can occur as a result of viewing stimuli
with certain spatial properties, including stripes and filtered noise patterns
of particular spatial frequency. This thesis is an exploration of the stimulus
properties causing discomfort, within the framework of two theoretical explanations.
Both of the explanations relate to the stimuli being difficult for the
visual system to process. The first is concerned with discomfort being the result
of inefficient neural processing. Neural activity requires energy to process
information, and stimuli that demand a lot of energy to be processed might be
uncomfortable. The second explanation revolves around uncomfortable stimuli
not being effective in driving the accommodative (focussing) response. Accommodation
relies on the stimulus as a cue to drive the response effectively - an
uninformative cue might result in discomfort from an uncertain accommodative
response. The following research investigates both these possibilities using a
combination of psychophysical experimentation, questionnaire-based surveys
on non-clinical populations, and computational modelling. The implications
of the work for clinical populations are also discussed.
Type
Thesis, PhD Doctor of Philosophy
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