Minimising risk from flashing lights
The last quarter of the calendar year is crammed full of public celebrations including Halloween, Fireworks Night, Diwali, Christmas and New Year's Eve. For anyone with photosensitive epilepsy, this can pose additional risk factors with flashing lights being very much part of the festive scene.
Dr Fergus Rugg-Gunn (right) said: ‘Photosensitive epilepsy is relatively rare affecting up to five per cent of people with epilepsy, but it can be very debilitating.
‘Flashing lights have become very much part of our culture but if the lights are flashing at between 3 and 30 flashes per second, they could potentially cause a problem for someone who is photosensitive. Most festive lights flash at around one hertz (one flash per second) which is too low to pose a risk, but several circuits flashing together could increase the risk rate.
‘Many public venues such as theatres and concert halls are very much aware of this and are careful to ensure any lighting effects are within the safety guidelines. The Health and Safety Executive recommends that strobe lighting in clubs flashes at a maximum of four flashes per second.
'But there are always cases of Christmas trees or other displays which do not comply and which may trigger a seizure.'
Other factors which may increase the risk of a seizure in those with photosensitive epilepsy include: tiredness, stress, sitting too close to a tv or computer screen, light and dark patterns moving quickly or changing directions and watching a screen in a darkened room.
If someone is unexpectedly exposed to a trigger, covering one eye completely with their hand will help to reduce the photosensitive effect.
About photosensitive epilepsy
- 1 in 20 people with epilepsy has photosensitive epilepsy
- Photosensitive epilepsy first came to prominence in the 1950s and was known as television epilepsy but is more than a modern phenomenon
- Flashing lights between the frequencies of 3 and 30 hertz (flashes per second) are most likely to trigger a seizure in 60% of people with photosensitive epilepsy, but some may be sensitive outside this range
- Photosensitive epilepsy can also be hereditary. If a woman has photosensitive epilepsy, her children have a 25% chance of developing it
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