Westcott, Mark; (1999) Improving the detection of abnormal visual function in glaucoma using High Spatial Resolution Perimetry and Motion Displacement Threshold testing. Doctoral thesis (M.D), UCL (University College London).

Text Improving_the_detection_of_abn.pdf Download (16MB)

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.

Download activity - last month

Export as JSONCSVXML

Download activity - last 12 months

Export as XMLCSVJSON

Downloads by country - last 12 months

Export as JSONXMLCSV

Archive Staff Only

View Item