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Light-sensitive migraine?
Around one in ten adults suffer from migraines. And three times more women than men will experience that blinding pain that sends millions into a dark room unable to cope with even a glimmer of light.
So what’s going on?
This brilliant review offers three potential explanations linked to an overall hyper-excitablity in the brain in migraineurs. High-contrast patterns and colours are well-known visual triggers.
But flicker is another hidden cause of low-grade discomfort, even in those who don’t suffer from migraines – Photophobia in migraine: A symptom cluster?
Your eyes are constantly moving around in high-speed ballistic leaps called ‘saccades’. Your brain stitches up those snapshots to build a stable picture of the outside world. Your brain decides where your eyes should jump next using information from the ‘corner of your eye’.
When the lights are flickering, the patterns of light and shade become unstable.
So that split-second prediction-leap sequence becomes much harder. Your reading speed and accuracy goes down – and people who are sensitive or stressed might start to feel a headache coming on – Fluorescent lighting, headaches and eyestrain.
Most people are surprised to learn that all lights flicker. That’s because the electricity that comes out of the sockets is delivered in waves or cycles. In Europe that’s 50 cycles per second or Hertz (USA is 60Hz). So everything that runs on electricity has an inbuilt pulse. The lights are no different.
The threshold where you can consciously see movement (the flicker fusion frequency) for most of us is around 50-90 Hertz, or cycles per second – Critical Flicker Fusion Frequency: A Narrative Review. But the threshold for that automomic physiological response is closer to 2,000Hz.
After 3 hours under lights with flicker rates of 100Hz, heart rate goes up even in those who don’t suffer from migraine. So what can you do?
Flash of brilliance
If you’re heading to the gym (or the dance floor), that pulsing light show could be helping you to learn the moves.
This team tailored the pulses of light to the individual’s alpha EEG rhythm (8-12 Hz or cycles per second) and delivered that frequency as pulses of light, synchronised to the trough of the cycle. The improved learning effects lasted to the following day! – Learning at your brain’s rhythm: individualized entrainment boosts learning for perceptual decisions.
Range: How Generalists Triumph in a Specialist World by David Epstein
An inspiring and comforting read for anyone who, like me, has ever felt insecure about being an incurable generalist when micro-niching seems to be the secret to success.
Reading this book was just the nudge I needed step out of the shadows and invite my Irish friends to join the opening of an exhibition of my glass work hosted by RSpace Gallery in Lisburn, sponsored by Crafts Council Ireland.
Links to a selection of the work are here.
Please join me for a talk and the opening on the 17th of February.
I’ll also be leading a hand’s on workshop on the 13th March, the last day.
See more information here.
Headache cure
If you’ve ever noticed a nasty buzzing, scratchy sound next to a dimmer switch or noticed a strange strobing effect on a video call, or maybe just felt irritable or had a bit of a headache without really understanding why, you may be suffering from flicker.
Your brain is on high alert all the time to notice any fast movement.
It will kick off the stress response long before your conscious brain has any idea what’s going on. If you’ve ever dodged a tennis ball you will know exactly what I mean!
What’s that got to do with the lights?
As you dim a light, you’re reducing the amount of electricity going into the system.
The simplest way to do that is to chop up the electricity into smaller and smaller bursts
with bigger and bigger gaps between them.
Ideally, your brain will add all those up to create the impression of less light overall
But when the light isn’t designed to dim correctly or there’s a problem with the dimmer switch itself, or there’s some other glitch, the system breaks down.
You get a buzzing in the switch and you get that low-grade irritation and stress which causes migraines. It can even kick off epileptic fits.
What’s the solution?
Well, ideally you will buy a light bulb that’s designed to dim and check the dimmer switch
is compatible with that technology.
But that will involve a professional and electricians often struggle to keep up because the technology is moving so fast.
The other solution is to go back to basics and choose a combination of light sources
with different brightnesses for the different kinds of tasks
Bright overhead, softer warmer low-level light. And a task light that delivers the light you need when you’re working.
That will reduce your risk of headache and cut your carbon footprint too.
Can’t promise to cure a hangover though!