Dr Tony Redmond
My main research interests are in basic and clinical psychophysics, specifically the translation of basic science for improvement of visual field tests both in the clinical setting when investigating conditions that affect retinal performance and for measuring functional endpoints in clinical trials. I am particularly interested in ways in which the major limitations of conventional visual field tests can be addressed.
Figure 1. Schematic spatial summation curve, demonstrating how threshold declines as stimulus ara is incresed. From Redmond et al, Optom Vis Sci, 2013.
Spatial summation with age and in disease.
Since the beginning of my research career, I have been interested in how the sensitivity of the visual field to stimuli of different size changes with age and in disease. My first studies investigated changes in spatial summation with age and in early glaucoma. These papers, published side-by-side in Investigative Ophthalmology and Visual Science showed that although spatial summation is unchanged with advancing age, a loss of sensitivity (to a small spot of light varying in brightness) in early glaucoma can be accounted for by an enlargement of the area of complete spatial summation (Ricco’s area). This has direct implications for the design of optimum stimuli for measuring the visual field in eye disease.
Figure 2. Frequency-of seeing curves for Goldmann stimuli I-VI at 36.2° visual field eccentricity, measured on an Octopus 900 perimeter (Haag-Streit, Koeniz, Switzerland)
Addressing the limitations of conventional visual field tests
My most recent work has focussed on characterising response variability to visual field stimuli with psychometric functions and exploring ways in which variability can be minimized to improve the identification of visual changes. I am also interested in how measurements of sensitivity to different stimuli are affected by non-neural changes in the eye that accompany age or eye disease (e.g. increased light scatter within the eye).
Figure 3. Vanishing optotypes. From Shah et al, Ophthalmic Physiol Opt, 2011
‘Reading the letters on the chart’ is probably the most familiar test of vision to anyone who has ever had an eye examination. Although the test is quick and simple, measurement variability can be significant, making it rather insensitive to subtle changes in vision that occur over time or in response to treatment. One contributing factor is the wide variation in legibility between letters. A recent study, in which I was involved, showed how vanishing optotype acuity is more uniform across letter alternatives than acuity to conventional letters.
Figure 4. The parafoveal cone mosaic, imaged with a modified Heidelberg Retina Tomograph III
I am principal investigator on a Fight For Sight funded project investigating the relationship between grating resolution acuity and parafoveal cone density, measured with a modified Heidelberg Retina Tomograph III
Financial Support and Awards
Travel grant; oral presentation award (1st prize) at 23rd Annual Dalhousie University Ophthalmology Research Meeting, Halifax, Canada
Fight for Sight Dr Hans and Mrs Gertrude Hirsch Award
‘Determining patient-specific baseline ganglion cell density using in vivo imaging of the retinal cone mosaic in glaucoma’.
Lead applicant: T Redmond. Co-applicant: RS Anderson. Collaborators: R Malik, DF Garway-Heath, SC Dakin, 2011-12.
George Giles Prize for Postgraduate Research Excellence (College of Optometrists), 2010
iPro Practice-based research grant, College of Optometrists,
‘Assessment of Optic Disc Photographs for Glaucoma by UK optometrists’.
Lead applicant: SE Hadwin. Co-applicants: T Redmond, DF Garway-Heath, RS Anderson, 2010-11
Research excellence oral presentation award, College of Optometrists Research Symposium, York, UK, 2010
Travel grant, (HPSS R&D N. Ireland, Recognised Research Group for Vision) for attendance at ARVO 2009, Ft. Lauderdale, USA
Travel grant, College of Optometrists for attendance at ARVO 2009, Ft. Lauderdale, USA
World Glaucoma Congress poster presentation award (2nd place), Boston, USA, 2009
Training Grant, (HPSS R&D N. Ireland, Recognised Research Group for Vision) for attendance at “Matlab programming for Cambridge Research Systems equipment”, Durham University, 2009
Travel grant, (HPSS R&D N. Ireland Recognised Research Group for Vision) for attendance at ARVO 2008, Ft. Lauderdale, USA
Travel grant, International Perimetric Society (IPS) for attendance at IPS 2008, Nara, Japan
Roger S Anderson,
University of Ulster, Coleraine / Moorfields Eye Hospital, London / UCL Institute of Ophthalmology, London, ‘Improving clinical measurements of visual function’
Paul H Artes,
Dept of Ophthalmology & Visual Sciences, Dalhousie University, Halifax, Canada, ‘Improving clinical measurements of visual function’
Bruce JW Evans,
Institute of Optometry, London, ‘Performance of UK optometrists in anterior chamber angle assessment’