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Quantitative Afterimage Assessment and Pupillometry: from a Novel Computer Application to Visual Funcitonalities

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Quantitative Afterimage Assessment and Pupillometry: from a Novel Computer Application to Visual Funcitonalities City Research Online City, University of London Institutional Repository Citation: Bi, Wei (2012). New objective and psychophysical techniques to study the processing of visual signals with emphasis on chromatic afterimages. (Unpublished Doctoral thesis, City University London) This is the unspecified version of the paper. This version of the publication may differ from the final published version. Permanent repository link: https://openaccess.city.ac.uk/id/eprint/2216/ Link to published version: Copyright: City Research Online aims to make research outputs of City, University of London available to a wider audience. Copyright and Moral Rights remain with the author(s) and/or copyright holders. URLs from City Research Online may be freely distributed and linked to. 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City Research Online: http://openaccess.city.ac.uk/ [email protected] NEW OBJECTIVE AND PSYCHOPHYSICAL TECHNIQUES TO STUDY THE PROCESSING OF VISUAL SIGNALS WITH EMPHASIS ON CHROMATIC AFTERIMAGES Wei Bi Doctor of Philosophy City University The Applied Vision Research Centre Department of Optometry and Visual Science September 2012 TABLE OF CONTENTS LIST OF TABLES ............................................................................................................................ 6 LIST OF FIGURES .......................................................................................................................... 7 ACKNOWLEDGEMENTS .............................................................................................................. 26 DECLARATION ............................................................................................................................. 27 ABSTRACT.................................................................................................................................... 28 ABBREVIATIONS AND SYMBOLS .............................................................................................. 29 1 INTRODUCTION .................................................................................................................... 30 1.1 ANATOMY AND PHYSIOLOGY OF THE EYE ......................................................................... 30 1.1.1 The structure of the eye ......................................................................................... 31 1.1.2 The structure of the retina ...................................................................................... 34 1.1.3 Post-receptoral and post-retinal processing .......................................................... 43 1.2 COLOUR VISION ........................................................................................................... 55 1.2.1 Normal trichromatic colour vision ........................................................................... 56 1.2.2 Anomalous trichromacies, dichromacies and monochromacies ............................ 57 1.2.3 Dichromacies & Monochromacies .......................................................................... 59 1.3 THE FUNCTION OF PUPIL ............................................................................................... 60 1.3.1 Anatomy of the iris – sphincter and dilator muscles ............................................... 62 1.3.2 Pupillary pathways ................................................................................................. 63 2 EQUIPMENT AND METHODS .............................................................................................. 66 2.1 INTRODUCTION ............................................................................................................ 66 2.2 PUPILLOMETRY ............................................................................................................ 66 2 2.3 ASSESSMENT OF VISUAL ACUITY ................................................................................... 68 2.4 COLOUR SENSITIVITY ASSESSMENT ............................................................................... 70 2.5 COHERENT MOTION TEST ............................................................................................. 73 2.6 MELANOPSIN APPARATUS – ISOLATION OF MELANOPSIN RESPONSE ................................... 74 2.7 QUANTITATIVE AFTERIMAGE ASSESSMENT ...................................................................... 76 3 THE DESIGN OF THE QAA TEST ........................................................................................ 80 3.1 INTRODUCTION ............................................................................................................ 80 3.2 REQUIREMENTS ........................................................................................................... 81 3.2.1 Functional requirements ......................................................................................... 82 3.2.2 Non-functional requirements .................................................................................. 83 3.3 SYSTEM DESIGN ........................................................................................................... 85 3.3.1 The modules of the QAA test ................................................................................. 86 3.3.2 The psychophysics module .................................................................................... 89 3.4 IMPLEMENTATION ......................................................................................................... 90 3.4.1 Implementation of the psychophysics module ....................................................... 91 3.4.2 The implementation of interfaces between modules.............................................. 94 3.5 MONITOR CALIBRATION FOR THE QAA ............................................................................ 95 3.5.1 The QAA calibration procedure .............................................................................. 96 3.5.2 The QAA calibration results ................................................................................... 97 3.5.3 The usage of calibration in the QAA application .................................................... 99 3.6 SUMMARY ................................................................................................................. 105 4 QUANTITATIVE AFTERIMAGE ASSESSMENT ................................................................ 107 4.1 INTRODUCTION .......................................................................................................... 107 3 4.2 METHODS ................................................................................................................. 109 4.3 RESULTS FROM NORMAL SUBJECTS .............................................................................. 112 4.3.1 The effect of the gap duration .............................................................................. 112 4.3.2 The effect of reference stimulus duration ............................................................. 113 4.3.3 The effect of the chromatic saturation of the reference stimulus ......................... 114 4.3.4 The effect of chromatic direction .......................................................................... 115 4.3.5 The effect of background luminance .................................................................... 117 4.4 RESULTS FROM DEUTERANOPES .................................................................................. 118 4.5 RESULTS FROM SUBJECTS WITH PALINOPSIA AND VISUAL SNOW ...................................... 121 4.6 MECHANISMS FOR CHROMATIC AFTERIMAGES................................................................ 124 4.6.1 Normal Trichromats .............................................................................................. 124 4.6.2 The afterimage thresholds reveal dichromacy ..................................................... 127 4.6.3 Pupil colour responses in dichromacy depend on signal difference from the two types of cones ............................................................................................................... 131 5 A STUDY OF PUPIL RESPONSE COMPONENTS IN NORMAL SUBJECTS AND IN PATIENTS WITH CONGENITAL OR ACQUIRED HEMIANOPIA ............................................. 140 5.1 INTRODUCTION .......................................................................................................... 140 5.2 METHODS ................................................................................................................. 142 5.2.1 Subjects ................................................................................................................ 142 5.2.2 Apparatus & pupillometry stimuli .......................................................................... 143 5.3 RESULTS................................................................................................................... 146 5.3.1 Pupil light reflex response measurements ........................................................... 146 5.3.2 Pupil colour responses measurements ................................................................ 151 5.4 DISCUSSION .............................................................................................................. 155 6 MELANOPSIN SIGNALS AND THE PUPIL
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