Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.812586
Title: Improving the detection of abnormal visual function in glaucoma using High Spatial Resolution Perimetry and Motion Displacement Threshold testing
Author: Westcott, Mark
Awarding Body: University of London
Current Institution: University College London (University of London)
Date of Award: 1999
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Abstract:
Primary open angle glaucoma is a major cause of blindness and visual disability. The introduction to this thesis summarises evidence that automated perimetry is not sensitive enough to detect early glaucomatous damage. This thesis investigates two novel tests of visual function which are Motion Displacement Threshold (MDT) testing and High Spatial Resolution Perimetry (HSRP). In chapter 4, motion reaction times are shown to be abnormally elevated in glaucoma patients as a function of threshold elevation. Their potential use as a marker for reliability is outlined. Chapter 5 reports that analysis of the slope of the frequency-of-seeing curve improves the sensitivity of the MDT test compared with analysis of the threshold alone. Chapter 6 describes the technique of High Spatial Resolution Perimetry (HSRP) and investigates its spatial resolution, repeatability and clinical use in glaucoma. Chapter 7, elevated Motion Displacement Thresholds (MDTs) are identified in glaucoma. These are shown to coexist in some cases with fine scale scotomas identified using HSRP. This suggests that an underlying factor contributing to MDT abnormalities in addition to selective magnocellular loss or reduced redundancy is sensitivity loss on a spatial scale too small to be measured by conventional perimetry. This led to the hypothesis that the orientation of the MDT stimulus could have a significant effect on motion threshold glaucoma, and that stimulus orientation might be incorporated in order to improve the sensitivity of the test. This hypothesis was tested in chapter 8, which identified increasing elevation of motion threshold for a line stimulus moving perpendicular to the retinal nerve fibre layer compared to a line stimulus moving parallel to the retinal nerve fibre layer in some glaucoma patients. The clinical significance of these studies is summarised in chapter 9 and future developments to improve the MDT and HSRP tests are discussed.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.812586  DOI: Not available
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