Photosensitive epilepsy is where someone has seizures that are triggered by flashing or flickering lights, or patterns. Any type of seizure could be triggered but tonic-clonic seizures are the most common.
There are 2 groups of people who have photosensitive epilepsy:
- People who only have seizures triggered by flashing or flickering lights, or patterns. This is sometimes called pure photosensitivity
- People who have seizures triggered by flashing or flickering lights or patterns but also have seizures at other times
Flashing and flickering lights
Different people will be affected by lights at different flash or flicker rates. Lights that flash or flicker between 16 and 25 times a second are the most likely to trigger seizures. But some people are sensitive to rates as low as 3 or as high as 60 a second.
Patterns
Different people will be affected by different types of pattern. Those patterns with a high contrast or some that move are more likely to trigger seizures.
How common is photosensitive epilepsy?
Around 3 in every 100 people with epilepsy have photosensitive epilepsy. If someone else in your family has photosensitive epilepsy, you are more likely to have it too. And if someone in your family has juvenile myoclonic epilepsy, you are also at higher risk of having photosensitive epilepsy.
There are many types of epilepsy and photosensitive epilepsy is most common in the following:
- Juvenile myoclonic epilepsy
- Childhood absence epilepsy
- West syndrome
- Lennox Gastaut syndrome
- Juvenile absence epilepsy
- Dravet syndrome
Is photosensitive epilepsy more common at a particular age?
Most people who develop photosensitive epilepsy are aged between 7 and 19 years old. But a small number of people who develop epilepsy as adults, also have photosensitive seizures. And some people who had photosensitive epilepsy as children, will continue having photosensitive seizures when they become adults. Females are more likely to have photosensitive epilepsy than males.
Are there tests that can show if I have photosensitive epilepsy?
Your doctor might ask you to have an electroencephalogram (EEG) test to see if you have photosensitive epilepsy. The EEG records the electrical signals from your brain on an EEG machine. During the test, you will be asked to look at some flashing lights, to see whether your brainwave patterns change. If they do, it may mean you have photosensitive epilepsy.
What is the treatment for photosensitive epilepsy?
The most common way to treat photosensitive epilepsy is with epilepsy medicines. This is to lower the risk of having a seizure. To reduce the risk further, try to avoid looking at things that you know can trigger a seizure.
If you find yourself coming across something that might trigger a seizure without warning:
- Don’t close your eyes (this could cause a flicker effect)
- Do cover one eye with the palm of your hand straight away
- Do turn away from the possible trigger
Doing these things reduces the number of brain cells that could be stimulated and in that way the risk of a seizure happening is reduced.
Find out more about possible seizure triggers for people with photosensitive epilepsy.
If you would like to see this information with references, visit the Advice and Information references section of our website or contact our Epilepsy Action freephone helpline on 0808 800 5050.
This information has been produced under the terms of The Information Standard.
- Updated June 2018To be reviewed June 2021
Comments: read the 11 comments or add yours
Comments
I have had seizures ever since I had a heart scan. When I was sitting up on the scanning table. I was very dizzy and nauseated. I struggled to walk to sit down beside my daughter who was waiting in the room as I took the test. I suddenly had two seizures on the floor. At home I had two more seizures and ambulance was called. After four years of hundreds of seizures I am going for a sleep deprives EEG tomorrow. I am so light sensitive, wear rose color glasses, react to flashing lights. florescence lights, fast editing etc...my question is will I react to the strobe lighting in the test more so with lack of sleep than having enough sleep or does it depend on my neurons response at the time? Do the neurons react regardless? I have had so many seizures in public it feels unnerving to go anywhere.
Hi Mary
It good your doctors are doing more test to try help with your epilepsy.
A sleep-deprived EEG test is done when you have had less sleep than usual. When you are tired, there is more chance that there will be unusual electrical activity in your brain.
As your seizures are so unpredictable you may find our safety information helpful. It has information on how to assess risks and how to help yourself feel more confident about going out.
I hope this test give you doctors some helpful information so they can help with your seizure control.
Regards
Diane
Epilepsy Action Helpline Team
Hi, my name is Erna and ive been seeing a nuerologist for a concussion ive had a few months back. I have not been diagnosed with epilepsy but i have had serious sensitivity to flickering lights. None of this use to bother me before, id even go to raves, but now something as simple as the sun perring through a moving fan gives me severe headaches confusion and i feel like i wanna faint. The other day a movie was on and they were shooting in the dark, the flash from the shots fired hurt my head and i couldnt see for a few seconds then for about 5 minutes all i could see was color spots mixed with my surroundings and my left leg twitched. Thankfully i was already sitting down but it did freak me out. My doctor has prescribed me a medication specifically for epilespy but for my chronic occipital pain. I follow up in a week and get results on some MRIs, MRAs, and an EEG (which hurt like hell) but what do i do or say if he tells me everything looks ok? Because clearly its not or at least i dont feel this is normal.
Hi there,
I am syafiq from malaysia,just wanna ask about this photosensitive seizure,is it will inherit to our ancestry in future.
Hi Syafiq,
Some types of epilepsy and seizures run in families and these include photosensitive seizures.
If someone’s epilepsy isn’t part of another medical condition, the chances of their child inheriting it is thought to be less than 15%. However, it also depends on other things such as how many other family members have epilepsy, the type of epilepsy and the age it started.
We have more information on our webpage about inheritance (https://www.epilepsy.org.uk/info/daily-life/having-baby/inheriting-epilepsy) that you might find useful. And if this is something you are worried about it might be a good idea to speak to your doctor.
Regards
Jess
Epilepsy Action Helpline services
Hi, I don't have photosensitive epilepsy but have a question about triggers. Are there any guidelines for web and app designers as these can have moving, flashing images. Two family members are work in web design industry, so I am keen to pass any information on to them. I know they would want to be made aware of any things to avoid when creating websites /apps.
Hi
I happened to come across your question while researching for the design of flashing alarms in accessible toilets and along with the information on this website, there is also useful information on the Epilepsy Society
What rate of flashing light can trigger seizures?
Between 3-30 hertz (flashes per second) are the common rates to trigger seizures but this varies from person to person. While some people are sensitive at frequencies up to 60 hertz, sensitivity under 3 hertz is not common.
What patterns can trigger seizures?
Some people are sensitive to geometric patterns with contrasts of light and dark such as stripes or bars. Patterns are more likely to be a trigger if they are changing direction or flashing, rather than if they are still or moving slowly in one direction.
Flashing, flickering or patterned effects can make people with or without epilepsy feel disorientated, uncomfortable or unwell. This does not necessarily mean they have photosensitive epilepsy.
Also on the Epilepsy Foundation website (US)
Generally, flashing lights most likely to trigger seizures are between the frequency of 5 to 30 flashes per second (Hertz)..................flashing alarms: • To reduce the likelihood of the strobe light triggering a seizure, the Epilepsy Foundation’s professional advisory board recommends that
o the flash rate be kept to under 2 Hertz with breaks every so often between flashes
o flashing lights should be placed at a distance from each other and set to flash together at the same time to avoid an increase in the number of individual flashes
Personally, we recommend no flashing images at all on websites or in presentations or apps. Some of our members also have problems with very strong contrasts in images, so websites should give users the option to change the background and font colours and also to have alternative text versions of images and diagrams and also not to use PDF documents without a text alternative as some text browsers and other browsers can't read PDF.
Hope this helps.
Flick Harris, Manchester Disabled People's Access Group
Hi Alison
Thank you for your kind offer to share information with your family.
We have details of a number of guidelines and laws that online content producers may want to consider.
https://www.epilepsy.org.uk/info/photosensitive-epilepsy/web-design
Regards
Diane
Epilepsy Action Helpline Team
Hi can anyone help I suffer with fibromyalgia I can not stand light be it sun light or or florescent lights stripes or any pattern that is repetitive I have not been diagnosed with photosensitive epilepsy feel permanently dizzy and don't feel in control with my legs just feel totally frustrated up to 3years ago I never had any of this it all started after I had a perforated ulcer emergency op done all these symptoms my doc said its my fibro anxiety I know iam giving mixed messages out but I don't know what to do be
Kind regards val
My 17yr old son has Autism,Generalised Epilepsy and SunFlower syndrome. His meds are Valporate and has Buccolam in case of a Tonic Clonic. His school insist that he should be able to learn how to travel independently on public transport. They want him to start a internship when he is 18yrs old We are extremely worried about this as he has emergency meds that he keeps with him wherever he goes and are always held by a teacher or assistant during his school day. How do other persons with the same conditions travel independently? Or don't they? Please advise
Hi Judith
It sounds as though there could be some exciting opportunities for your son. But I can appreciate that you will have concerns about his safety as well.
Many people we talk to use public transport but we also know that some people with epilepsy feel the risk for them is too great. We have some information about staying safe outside which may be a helpful starting point for you to look at. But a lot depends on what the risk factors are for your son and how school plans to manage these risks.
Whoever is helping your son to learn to travel independently must put a risk assessment in place. This will ensure that they have assessed that the activity is safe and it will specify what should happen in an emergency. I wonder if it would be possible for you and your son to ask to see the risk assessment. This may help you to raise any concerns you might still have about his wellbeing and safety.
I hope you can find a way forward that works for your son. If we can be of any more help you would be welcome to contact the Helpline and speak to one of our advisers.
Regards
Mags
Epilepsy Action Helpline Team