Mid Sussex/Brighton VTS Migraine prevention using colour filters Dr Yolande Knight GP ST2 Mid Sussex/Brighton VTS

Basic migraine pathophysiology Cortical hyperexcitability Introduction Introduction Concepts Basic migraine pathophysiology Cortical hyperexcitability Visual stress Precision spectral filters and ophthalmic tints Evidence 'Seeing the light' Clinical application

Migraine pathophysiology- cortical excitability Visual aura, photophobia Visual triggers www.CGRPinmigraine.com (Merck)

Migraine pathophysiology- cortical hyperexcitability www.CGRPinmigraine.com (Merck)

Migraine art- the perceptual experience of migraine

Visual stress- aversive art Bridget Riley exhibition. Daily Telegraph (1971): guards complained of headaches and requested dark glasses

Visual stress- uncomfortable art Most uncomfortable images Least uncomfortable images AJ Wilkins, 2006

Visual stress- aversive imagery from a migraineur's view www.debbieaylesartist.co.uk

Visual stress- aversive 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 Pages of print can resemble visually stressful patterns

Visual stress- spatial frequency and threshold of discomfort Some people find striped patterns uncomfortable to look at The discomfort depends on the spatial frequency of the stripes (AJ Wilkins, 2006) Spatial frequency: 3 cycles per degree Degree of discomfort depends on individual susceptibility Migraineurs experience discomfort from patterns causing only mild aversion in non-migraineurs, typically 3 cycles/degree

Visual stress- symptoms and signs Also known as Irlens syndrome Co-morbid with migraine? Or a sub-symptom of migraine? Associated with dyslexia Visual distortions Illusions of motion, shape, colour Reading difficulties Physiological symptoms Eye strain Nausea Headache Seizures Signs Using finger as a marker for reading Skipping words Excessive blinking

Visual stress- mechanism and manipulation Hyperexcitability in the visual cortex Hypothetical manipulation 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 Which colour reduces hyperexcitability is 'specific to the individual'

Assessing visual stress- colorimetry 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

Coloured plastic sheet to overlay on text POTs in practice Cerium manufactures Precision Tinted Lenses (PTL) Spectacles Contact Lenses Coloured Overlays Coloured plastic sheet to overlay on text

The effect of POTs on reading

Evidence - Precision Ophthalmic Tints (POT) in migraine Wilkins et al. Cephalalgia 2011. N=11 migraineurs 9/11 h/o visual triggers for migraine 7/11 MwA 11/11 experienced illusions/distortions during study fMRI Reduced cortical activation in V2 in migraineurs wearing POT under visual stress visual discomfort score (/10) 8.0±2.1 without lens 2.4±1.7 with POT lens

Evidence - Coloured lenses in migraine Huang et al. Cephalalgia 2002. N=17 migraineurs 12/17 MwA 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. Visual evoked potentials N=12 MwA vs controls Glasses in red, green, yellow, blue, grey No effect in MwA

Evidence - rose tinted spectacles... Good et al. Headache 1991. 20 children with clinically diagnosed migraine Rose vs blue tint for 4 months 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? Noseda R et al. Nat Neurosci. 2010 Posterior thalamo-cortical neurons that are both dura- and light-sensitive apposing photo-regulatory retinal ganglion axons

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 colour lenses RCTs are lacking 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 Cost £55 each colorimetry test, performed twice before precision lenses made £90 to make coloured lenses Total £200 Local variance in DLA/subsidized costs Optometrists Check on the Cerium website for nearest specialist Optometrist with an appropriate Intuitive Colorimeter www.ceriumoptical.com Irlen support www.irlen.co.uk