Migraine prevention
using colour filters
Dr Yolande Knight
GP ST2
Mid Sussex/Brighton VTS
Introduction
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Introduction
Concepts
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Basic migraine pathophysiology
Cortical hyperexcitability
Visual stress
Precision spectral filters and ophthalmic tints
Evidence
'Seeing the light'
Clinical application
Migraine pathophysiology
Migraine pathophysiology- cortical excitability
Visual aura,
photophobia
Visual triggers
www.CGRPinmigraine.com (Merck)
Migraine pathophysiology- cortical hyperexcitability
www.CGRPinmigraine.com (Merck)
Migraine artthe perceptual experience of migraine
Visual stress- aversive art
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Bridget Riley exhibition. Daily Telegraph (1971): guards
complained of headaches and requested dark glasses
Visual stressuncomfortable art
Most uncomfortable images
Least uncomfortable images
AJ Wilkins, 2006
Visual stressaversive imagery from a migraineur's view
www.debbieaylesartist.co.uk
Visual stressaversive imagery from a migraineur's view
www.debbieaylesartist.co.uk
Visual stress- visual environments
Pretty J, Peacock J, Sellens M and Griffin M. 2005. Int'l Journal of Environmental Health Research 15(5), 319-337
Text as a visual stressor
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Pages of print can resemble visually stressful patterns
Visual stressspatial frequency and threshold of discomfort
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Some people find striped patterns uncomfortable to look at
The discomfort depends on the spatial frequency of the
stripes
Spatial frequency: 3
cycles per degree
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(AJ Wilkins, 2006)
Degree of discomfort depends on individual susceptibility
Migraineurs experience discomfort from patterns causing only
mild aversion in non-migraineurs, typically 3 cycles/degree
Visual stresssymptoms and signs
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Visual stress
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Also known as Irlens syndrome
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Co-morbid with migraine? Or a sub-symptom of migraine?
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Associated with dyslexia
Visual distortions
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Illusions of motion, shape, colour
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Reading difficulties
Physiological symptoms
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Eye strain
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Nausea
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Headache
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Seizures
Signs
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Using finger as a marker for reading
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Skipping words
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Excessive blinking
Visual stressmechanism and manipulation
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Mechanism
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Hyperexcitability in the visual cortex
Hypothetical manipulation
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Pattern of excitation in ophthalmic cortex neurons changes in
response to colour stimulus, either by direct stimulus of that
colour or absorption of opposing colour
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Which colour reduces hyperexcitability is 'specific to the
individual'
Assessing visual stresscolorimetry
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Intuitive Colorimeter projects coloured light onto a page of
text found to be stressful or aversive to the migraineur
Manipulate hue and saturation to identify the most
comfortable colour (of 100,000 possible colours)
Replace text with a stressful stripe pattern of 3cpd to test the
effectiveness of this particular colour in reducing visual
stress
POTs in practice
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Cerium manufactures Precision Tinted Lenses (PTL)
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Spectacles
Contact Lenses
Coloured Overlays
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Coloured plastic sheet to overlay on text
The effect of POTs on reading
Evidence Precision Ophthalmic Tints (POT) in migraine
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Wilkins et al. Cephalalgia 2011.
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N=11 migraineurs
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fMRI
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9/11 h/o visual triggers for migraine
7/11 MwA
11/11 experienced illusions/distortions during study
Reduced cortical activation in V2 in migraineurs
wearing POT under visual stress
visual discomfort score (/10)
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8.0±2.1 without lens
2.4±1.7 with POT lens
Evidence Coloured lenses in migraine
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Huang et al. Cephalalgia 2002.
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N=17 migraineurs
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12/17 MwA
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In 45% of MwA patients, headache frequency reduced by
50% or more on days when POTs were worn versus days
wearing control colour lens
Afra et al. Headache 2000.
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Visual evoked potentials
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N=12 MwA vs controls
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Glasses in red, green, yellow, blue, grey
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No effect in MwA
Evidence rose tinted spectacles...
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Good et al. Headache 1991.
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20 children with clinically diagnosed migraine
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Rose vs blue tint for 4 months
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After 4 months, those with rose tint had mean h/a
frequency improve from 6.2 episodes to 1.6 per month
Mechanism of light-sensitivity in migraine?
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Noseda R et al. Nat Neurosci. 2010
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Posterior thalamo-cortical neurons that are both duraand light-sensitive apposing photo-regulatory retinal
ganglion axons
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Seeing the wood for the trees
Pros
Cons
Some supportive studies in migraineurs,
albeit with small numbers
Field is dominated by 1 lead researcher
(Wilkins) who also worked with Cerium and
MRC to develop the Intuitive Colorimeter and
lens specs.
No significant reported side effects of wearing RCTs are lacking
colour lenses
Does not require GP referral. Direct
attendance at Optometrist
Within the Ophthalm field there is some
scepticism about Irlen and her theories of
visual stress
Low cost to the NHS: private payment
American Academy of Paediatrics does not
believe there is any scientific basis for the use
of coloured lenses in children to treat 'visual
stress' because “the method used to select
the lens or filter colour has been highly
variable,the colour selection has also shown
considerable variability,and the test-retest
consistency has been poor”
American Assoc of Optometrists and of
Ophthalmologists believes there is no
evidence for use of coloured lenses nor of a
distinct Irlen syndrome entity
Information for patients
Wear the tinted glasses for all daily activities
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Cost
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£55 each colorimetry test, performed twice before
precision lenses made
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£90 to make coloured lenses
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Total £200
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Local variance in DLA/subsidized costs
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Optometrists
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Check on the Cerium website for nearest specialist
Optometrist with an appropriate Intuitive Colorimeter
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www.ceriumoptical.com
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Irlen support
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www.irlen.co.uk
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