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Title: New methods and tools for improving the contrast sensitivity of people with central visual field impairment using temporal image modulations
Author: Watson, Lynne Michelle
Awarding Body: Glasgow Caledonian University
Current Institution: Glasgow Caledonian University
Date of Award: 2013
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Healthy macular function is a necessary prerequisite for the performance of fine detailed visual tasks such as reading and accurate face perception. Impairment of central vision follows the onset of age related macular degeneration (AMD) which has long been identified as the most prevalent ocular pathology affecting the elderly population of developed countries. The inherent coarse sampling ability of peripheral retinal neurones forces the individuals to construct their visual world from blurred low spatial frequency patterns. The magnocellular visual pathway is tuned to such low spatial frequency images and responds vigorously to fast modulations of luminance contrast, exhibiting band-pass temporal frequency characteristics. This suggests that temporal modulations of visual objects could enhance the performance of people who primarily perceive images of low spatial frequency content. Normal fixational eye movements are thought to counteract neural adaptation by jittering stationary images over the receptive fields of visual neurones, producing transient bursts of neural spikes. The retinal image shifts, produced by fixational eye movements, are not large enough to elicit neuronal activity during exposure of low spatial frequency images. Retinal image shifts with larger amplitudes, however, could produce activation of magnocellular neurones during the stimulus exposure and thus enhance contrast sensitivity to low spatial frequency images.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available