Can flashing lights cause epileptic fits?

[Rohloff_Brompton_Rider]

On my ride last night, a pedestrian complained my lights "were not very good for epileptics", he was a young lad about eighteen at a guess and didn't appear to be being nasty, more off concerned tone of voice.


On the front I have a smart light 35 watt in flashing mode and a maglite xl200 which has a vey rapid and bright-ish flash mode.

Has he got a point? Can I unintentionally cause someone to have a fit?

 

[ufkacbln]

Photo-epilepsy is triggered by brightness and speed.

The British Epilepsy Association, the Epilepsy Alliance, and Epilepsy Action concur and have stated:

Red flashing bicycle lights

Red flashing bicycle lights (light emitting diodes, or LEDS) have triggered seizures in a small number of people. This has happened when they were very close to the lights, setting them up.

The flash rate is outside the trigger threshold, however factual evidence is not always accepted in such emotive subjects

Other groups list bicycle lights as "potential" triggers.

The Brighton experience is typical. Note the use or the words "could", "expressed concern" as opposed to "have"

Lights on bikes make us have fits, say Brighton and Hove epileptics

2:40pm Thursday 28th January 2010
Cyclists are being urged to stop using fast-flashing bike lights over fears they could trigger epileptic fits.

The Brighton and Hove branch of Epilepsy Action, the group which represents hundreds of thousands of people who suffer from the condition, expressed its concern about the rapidly flickering beacons after several of its members experienced problems.
The organisation said the lights cause people with the condition to feel ill and disorientated adding it could trigger partial seizures and full-blown convulsions.

In a letter addressed to Brighton and Hove cycling group Bricycles, the branch requested cyclists in the city ditch the flickering lights in favour of a continuous shining lamp.

The group said action needed to be taken about both rear and front lights.

Chris Juden, of CTC, the UK’s national organisation for cyclists, said people using bikes had to balance "possible discomfort" for pedestrians against the risk of traumatic injury or death for cyclists.
Mr Juden added steps, such as a law stating lights cannot flash more than four times a second, had already been taken to avoid triggering epilepsy.

Basically if you have standard lights then there is no proven link or recorded incident in normal use with the triggering of epileptic fits.

 

[shouldbeinbed]

you never know but as they're pretty ubiquitous, you zip past people pretty quickly so aren't exposing them to it for long and as there aren't people falling down on the pavements in any great number I wouldn;t worry too much.

I guess the ones built to a national standard (so rule out the chinese cheapies) have to have some sort of checks done to avoid the usual trigger frequency for epileptic attacks.

My fenix-alike Dealextreme import torch does have a freaky and very fast random flash mode that I would be concerned about setting off near someone with epilepsy though. I never inflict that particular mode on the general public because it is painful to look at for someone not usually bothered by flashy lights..

 

[Biker Joe]

Possibly as some flashing bike lights are very bright.
On the other hand, if I was so afflicted, and a flashing light was coming towards me I would avert my eyes or close them until the danger was past.
Good question.

 

[Rohloff_Brompton_Rider]

Possibly as some flashing bike lights are very bright.
On the other hand, if I was so afflicted, and a flashing light was coming towards me I would avert my eyes or close them until the danger was past.
Good question.

Hehehe....they'd have to shut them for twenty minutes because of the slow speed I climb the hill upto sharneyford....

 

[ColinJ]

I have a front light with two flash modes. One mode slowly flashes SOS in Morse. The other mode flashes the light so fast that it does me in, and AFAIK I don't even suffer from epilepsy!

My stepdaughter suffered minor epileptic episodes when she was young where she'd go 'vacant' for no apparent reason. Tests with a flashing light showed that these episodes were not difficult to trigger. She seems to have grown out of the problem now.

 

[machew]

If her indoors is due for a seizure then the flashing lights from my bike can trigger one.

 

[Rohloff_Brompton_Rider]

Oh dear, I don't want to be the cause of someone's distress, I'll put my lights on solid and recharge daily.

 

[ColinJ]

Oh dear, I don't want to be the cause of someone's distress, I'll put my lights on solid and recharge daily.

I think having a lower-power flashing light on as well as the main one could still be eye-catching, but be unlikely to cause problems. Wouldn't help with battery life, of course.

 

[Kookas]

There are plenty of LED lights on the backs of pricey German cars and even in traffic lights, and although they flash much, much faster (to the point that they appear to be solid) and are much brighter than (most) bike lights I don't read too many complaints about those.

 

[Drago]

Photosensitive epilepsy is massively bigged up, mainly thanks to a scene in The Andromeda Strain where a scientist has a fit because of a flashing red emergency light.

Only 3% of those with epilepsy have this form, and the majority of those are sensitive in the 16-25hz region, which is very fast. Flashing strip lights, tv's, bike lights etc are simply not capable of triggering such an episode. There is some variance outside this threshold but its very, very rare. What the British Epilieptic Association claim about bike lights is not backed up be any science. I know all this because my youngest niece suffers.

 

[Little yellow Brompton]

On my ride last night, a pedestrian complained my lights "were not very good for epileptics", he was a young lad about eighteen at a guess and didn't appear to be being nasty, more off concerned tone of voice.


On the front I have a smart light 35 watt in flashing mode and a maglite xl200 which has a vey rapid and bright-ish flash mode.

Has he got a point? Can I unintentionally cause someone to have a fit?

He doesn't , very much like the "flash photography" warning, it's misplaced concern by third parties, the flash rate is no where near high enough, and the contrast is not strong enough.

 

[gaz]

I've seen a few bike lights which flash at faster than 10hz and they are flipping annoying. Anything more than 4Hz is overkill.

 

[antnee]

As an old epileptic I can safely say that If I went to a disco I would perhaps fit. But as most of the flashing lights on bikes are nowhere near as bright as in a Disco I can't myself say that it does affect me, but then perhaps I'm not as epileptic as some other people are as it is an affliction of different degrees.

 

[geo]

Can understand your concern,however in my opinion flashing lights are the best way to get me noticed and hence keep me as safe as possible on the bike. So I will continue in flashing mode, as has been stated if your affected dont look at them.