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Colour in the prevention of visual discomfort 

Latest research!

Held Sunday, November 14th, 2021

This conference was hosted jointly by the University of Essex and Cerium Visual Technologies and presented some of the latest research findings concerning the physiology of colour, the neurological effects of coloured filters, and the differential diagnosis of the visual stress that coloured filters are designed to relieve.


Over the last decade the use of coloured filters to reduce anomalous visual perception and discomfort has become a widespread specialism among optometrists around the world.

Expert overviews and recordings

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Prof Arnold Wilkins (UK)

“Use of coloured filters in neurological conditions”

Professor Emeritus, Department of Psychology, University of Essex  

Professor Wilkins is the leading authority on visual stress and the use of colour to mitigate the associated symptoms. While a senior researcher in the Cognition and Brain Sciences Unit of the Medical Research Council (UK), Wilkins developed the Intuitive Colorimeter® device that is used today in vision research and teaching schools. It is the primary medical device for determining the optimal filter tint for relieving visual stress.


Dr. Wilkins has written several books and been published several hundred times in peer-reviewed psychology, neurology, optometry, ophthalmology, and education journals.  

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Dr Olivier 
Penacchio (UK) 


Dr Sarah
Haigh (USA) 


Dr Gordon
Plant (UK)

"Visual discomfort and statistical regularities in natural scenes" 

School of Psychology and Neuroscience - Senior Research Fellow (Visual Salience) - University of St Andrews - UK  

“Visual discomfort

and cortical excitability"

Assistant Professor, University of Nevada, Reno, Department of Psychology and Center for Integrative Neuroscience

“Where are we with Visual Snow?” 

Neuro-Ophthalmologist, National Hospital for Neurology and Neurosurgery, Moorfields Eye Hospital, and University College, London 

Recent research publications: 

  • Pattern-sensitive patients with epilepsy use uncomfortable visual stimuli to self-induce seizures 

  • Chromatic induction in migraine 

  • Visual stress responses to static images are associated with symptoms of Persistent Postural Perceptual Dizziness (PPPD) 

  • The influence of typography on algorithms that predict the speed and comfort of reading 

Research interests: 

  • Neurological responses to basic sensory stimuli and the impact on sensory-related cognition. 

  • Underlying pathophysiology in clinical conditions including autism, migraine or traumatic brain injury. 

  • Establishing methods for improving sensory processing to have cascading improvements on complex cognitive processing. 

Recent research publications: 

  • Neurological disorders that affect vision. 

  • Photophobia in migraine: A symptom cluster? 

  • Visual Illusions and Hallucinations in Healthy and Disordered Eyes and Brains  


Dr Douglas Vilhena (BR)

“Coloured overlays and reading" 

PhD in Neuropsychology, Universidade Federal de Minas Gerais, Brazil and Universidade do Porto, Portugal 

Coordinator of the Laboratory of Applied Research in Neuroscience of Vision (LAPAN-UFMG). President of the Brazilian Congress of Neurovision (UFMG), and Project Manager of II World Dyslexia Forum. 


Prof Bruce Evans (UK)

"The differential diagnosis of visual stress” 

Director of Research, Institute of Optometry and Visiting Professor, Division of Optometry and Visual Sciences, City University and London South Bank University, Optometrist and Director of independent optometric practice, Brentwood, Essex UK 

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Ms Karen
Monet (CA)

“Repeated colorimetry and symptom reduction in head injury”

Director, Opticalm Visual Stress Clinic and CEO Opticalm Inc. Ottawa 

Recent research and interests:

  • Spectral overlays for reading difficulties: Oculomotor function and reading efficiency among children and adolescents with Visual Stress 

  • Effect of spectral overlays on visual parameters and reading ability: Integrative review from 1980 to 2008 

  • Visual stress associated with reading difficulties: prevalence and intervention in elementary school students 

Research interests: 

  • Dyslexia, visual factors, and the role of eye care professional 

  • Sensory visual stress (a.k.a. Meares-Irlen Syndrome) 

  • Practical diagnostic guidelines for visual stress (pattern-related visual stress) 

Research and related interests: 

  • Effectiveness of Intuitive Colorimetry in the reduction of visual discomfort in neurological and neurodevelopmental conditions (migraines, acquired brain injury, lyme disease, autism, ADHD, etc).  

  • Additional assistive tools and technologies for reduction of visual stress triggers in school and work environments. 

  • Standardized systems for the management of Visual Stress assessments, reporting and research. 

Full Conference Recording

We are delighted to highlight these fascinating research developments - many more individuals could potentially be helped though the use of precision colour, and it’s important that this research be given a suitable platform so this knowledge can be shared appropriately.

- Kimberley Harrison,

   Managing director of Cerium Visual Technologies


OT Optometry Today - Interview with​ Prof Arnold Wilkins


OT spoke to Professor Arnold Wilkins, emeritus professor for the University of Essex and the designer of the Intuitive Colorimeter, about the plans for the conference.

What is the main aim of the conference? What do you hope practitioners will take away from the event?

Professor Arnold Wilkins (AW): The main aim is to bring practitioners up to date with developments in the theory underlying precision ophthalmic tints, with the best way of diagnosing visual stress and with the range of conditions that can benefit from tints.
What would you say are the biggest developments in visual stress and coloured filters in recent years?

AW: Visual stress has been shown to be a component of the difficulties experienced in a wide range of neurological conditions including migraine, autism, photosensitive epilepsy, stroke, head injury and possibly cluster headache. 
What will be the key message of your session, ‘Use of coloured filters in neurological conditions’?

AW: The key message is that when the visual cortex is rendered hyper excitable by neurological disorders, coloured filters can help reduce the adverse consequences for visual functioning. It is reasonable to suppose that the visual cortex is hyper excitable in all the neurological disorders listed above. 
For me, the most exciting development, still in its early stages, is the possibility of using tints to treat the prodrome – warning – in cluster headache. Cluster headache is rare but excruciating. There are early indications that it may, sometimes, be possible to prevent the development of the prodrome into cluster headache. The prospect of a safe non-invasive treatment for this disabling condition is very exciting. 
What would be your key advice for understanding visual stress and the use of coloured filters? 

AW: The visual world in which we now live is stressful, and our brains have not yet evolved to process them efficiently. We have shown this to be the case, not only as regards the spatial arrangement of contours, but also as regards their chromaticity. We have shown how current typographic practice is suboptimal for efficient vision, and how simple changes can improve matters. 
The recognition of the visual stress in current urban living, and of its origins, should mean that we can move towards a visually less stressful environment. Until then, coloured filters are a necessary treatment for individuals who are particularly susceptible.

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