Yr Athro David Whitaker

Professor David Whitaker

Director of Teaching

School of Optometry and Vision Sciences

Mae'r cynnwys hwn ar gael yn Saesneg yn unig.

Research Overview

My existing interest in cue combination within a single sensory system (vision) has more recently expanded to the interaction between different senses (audition, vision and touch). Ours was the first study to co-vary cue reliability across these senses and demonstrate that the overall, combined percept is critically dependent upon the relative salience of the sensory inputs. This work has evolved into the study of sensory time – how we perceive the duration and the temporal order of events within and across the senses. Our findings point to the intriguing prospect that time and space may be processed in very similar ways within the human brain. Neural ‘channels’ have long been established in the processing of visual and auditory space and our recent findings support the existence of ‘time channels’ in the temporal domain.

Previous research has included displacement thresholds, a type of visual hyperacuity, the roles of neural and optical factors in vision loss with increasing age, peripheral vision, stimulated by the ‘cortical magnification theory’ of vision, disability glare – the reduction in visual performance produced by a glare source, and I maintain an interest in the phenomenon of crowding in peripheral vision, including various aspects of the limitations of reading in peripheral vision.

Teaching Overview

I am currently Professor and Director of Learning & Teaching, School of Optometry & Vision Sciences at Cardiff University and an honoury visiting Professor at the University of Nottingham.

Education

1984-1987 - University of Bradford: PhD "Displacement thresholds in oscillatory movement perception".

1980-1983 - University of Bradford: BSc (1st class Hons.): Ophthalmic Optics (Optometry)

1971 - 1979 - Bradford Grammar School: Maths A-level (A), Physics A-level (A), Chemistry A-level (A)

Academic and Professional Appointments

Sept 2015 – present Professor and Director of Learning & Teaching, School of Optometry & Vision Sciences, Cardiff University

2013 Appointed to REF2014 as a member of sub-panel 3: Allied Health Professions

August 2010 – present Honorary Visiting Professor, University of Nottingham.

2010 - 2014 Senior Vice President, Association of Optometrists.

August 2009 - present External Examiner, European Council of Optometry and Optics.

2008 Specialist Advisor RAE2008 UoA12b, UK Higher Education Funding Council.

October 2006 - present Panel Visitor (Panel Chair 2010-14), General Optical Council.

June 2005 - 2010 Vice President, Association of Optometrists.

Oct 2004 – Feb 2014 External Moderator, Association of British Dispensing Opticians

July 2003 - Sept 2004 Acting Dean, School of Life Sciences, University of Bradford.

Apr 2000 – August 2015 Professor of Vision Science, Bradford School of Optometry and Vision Science, University of Bradford.

April 2000 - Jan 2004 Head of Department, Optometry, University of Bradford.

Sept 1996 - March 2000 Reader, Department of Optometry, University of Bradford.

Jan 1995 - Aug 1996 Senior Lecturer, Department of Optometry, University of Bradford.

Sept 1987 - Dec 1994 Lecturer, Department of Vision Sciences, Aston University.

Jan 1984 - July 1987 Pre-registration Optometrist, St James's Hospital, Leeds.

Jul 1983 - Jan 1984 Postgraduate Student, Department of Optometry, University of Bradford.

Professional memberships

Member of the College of Optometrists (MCOptom)

Registered as an Optometrist with the General Optical Council

Teaching

Since my first lectureship post in 1987, my teaching has centered on the subject of Ophthalmic Lenses and Dispensing in 1st and 2nd years of the programme. I have developed efficient modes of delivery, particularly in practical sessions. This has been achieved through the development of station-based modes of assessment, in which students are required to carry out specific, well-defined practical tasks and are assessed on the accuracy of their results, rather than upon the methodology which they use. Careful task design ensures that students who adopt an unsatisfactory methodology would produce incorrect results.

I have also been a postgraduate supervisor since 1988, supervising a wide range of successfully awarded PhDs.

Displacement thresholds

My early publications arose from doctoral work into displacement thresholds, a type of visual hyperacuity. This interest in hyperacuity, particularly in how the visual system determines the relative position of objects in the world around us, continues to the present day. Experiments into the spatiotemporal characteristics of displacement thresholds soon progressed into potential clinical use of the test to determine visual function behind optical media opacities, principally cataract. Hyperacuities were known to be resistant to image degradation, yet susceptible to retinal disorders such as macular degeneration. This work culminated in 1989 with clinical studies to examine the efficacy of the displacement threshold test. Although these studies demonstrated the success of the technique, the ever increasing success of cataract surgery limits the impact of the problem.

The roles of neural and optical factors in vision loss with increasing age

Another clinical interest concerns the roles of neural and optical factors in vision loss with increasing age. In a series of experiments we highlighted the relative importance of neural factors in determining the normal age-related decline in human vision. This highly-cited area of research included quantifying changes in pupil size with age, an issue which has since become important in the areas of refractive surgery and ocular aberrations.

Periphal vision

Early in the 1990s I became interested in peripheral vision, stimulated by the ‘cortical magnification theory’ of vision in which it was thought that peripheral visual performance on all visual tasks could be equated by the application of an eccentricity-dependent magnification factor. We demonstrated that different tasks required substantially different amounts of magnification in peripheral vision in order to be equated to foveal performance levels. This represented a marked departure from the classical ‘cortical magnification theory’. From an ecological perspective it makes sense that the visual mechanisms devoted to a task such as movement detection should be relatively evenly distributed across the visual field, thereby allowing swift and accurate detection of potentially threatening objects. Alternatively, for tasks that involve detailed positional relationships of static objects, visual mechanisms may be concentrated at the fovea and the task best accomplished by foveation of the stimulus.

Disability glare

More clinical interests re-surfaced in the early 1990s in which we addressed a longstanding debate regarding disability glare – the reduction in visual performance produced by a glare source. We highlighted the simplistic nature of the mechanism of disability glare as a purely optical phenomenon, showing that intraocular straylight could be conveniently assessed by measurements of disability glare.

Crowding in peripheral vision

I maintain an interest in the phenomenon of crowding in peripheral vision, including various aspects of the limitations of reading in peripheral vision. Other work has investigated the functional sub-divisions of human vision by studying second-order, texture processing mechanisms and providing psychophysical evidence regarding a functionally dedicated visual pathway for texture analysis and the relationship to its first-order input. We have adopted the fruitful approach of investigating characteristics of visual misperceptions (illusions) to elucidate structural and functional properties of human vision, and this strategy has led to published output in some of neuroscience’s most prestigious journals.

Cue combination within a single sensory system

My existing interest in cue combination within a single sensory system (vision) has more recently expanded to the interaction between different senses (audition, vision and touch). Ours was the first study to co-vary cue reliability across these senses and demonstrate that the overall, combined percept is critically dependent upon the relative salience of the sensory inputs. This work has evolved into the study of sensory time – how we perceive the duration and the temporal order of events within and across the senses. Our findings point to the intriguing prospect that time and space may be processed in very similar ways within the human brain. Neural ‘channels’ have long been established in the processing of visual and auditory space and our recent findings support the existence of ‘time channels’ in the temporal domain.

Past projects

PeriodNameFinancial SuportOutcome
2013-presentCorinne FulcherFODOOngoing
2012-presentChris LongleyCollege of OptometristsOngoing
2008-2012John HotchkissClinical DemonstratorPhD Awarded
2004-2008James HansonClinical DemonstratorPhD Awarded
2002-2005Chara VakrouDepartmental StudentshipPhD Awarded
2002-2005James HeronClinical DemonstratorPhD Awarded
1999-2003Jennifer SkillenDepartmental StudentshipPhD Awarded
1995-1996Galal Mohamed IsmailSudanese governmentPhD Awarded
1995-1996Edwin MitchellHoffman La RochePhD Awarded
1991-1995Keziah LathamUnited Kingdom Science and Engineering Research CouncilPhD Awarded
1991-1995Richard SteenBritish College of OptometristsPhD Awarded
1990-1994Pia MäkeläAssociation of Finnish OptometristsPhD Awarded
1988-1991David MacVeighAston University StudentshipPhD Awarded