Contents
- Introduction
- About photosensitive epilepsy
- About hertz (Hz)
- Diagnosing photosensitive epilepsy
- Ways to reduce the risk of seizures if you have photosensitive epilepsy
- Some possible seizure triggers for people with photosensitive epilepsy
- Computer and television screens
- Useful information and contacts
Introduction
The aim of this information is to tell you what photosensitive epilepsy is, who it affects and what might trigger a seizure if you have photosensitive epilepsy. There are also suggestions for reducing the risk of having a seizure.
About photosensitive epilepsy
Photosensitive epilepsy is a type of epilepsy, in which all, or almost all, seizures are triggered by flashing or flickering light. Both natural and artificial light may trigger seizures. Some patterns, like stripes or checks, can also trigger seizures for some people with photosensitive epilepsy.
Various types of seizure can be triggered by flashing or flickering light. These include tonic-clonic, absence, myoclonic and focal seizures. The most common is a tonic-clonic seizure. The seizure(s) will usually happen at the time of, or shortly after, looking at the trigger.
Around three in every 100 people with epilepsy have photosensitive epilepsy. It usually begins before the age of 20, most commonly between the ages of seven and 19. Photosensitive epilepsy affects more girls than boys.
Epilepsy Action has more information about epileptic seizures.
About hertz (Hz)
The word hertz (Hz) refers to how often something happens in a second. For example, it can mean the number of times something flashes or flickers in one second. It can also mean the number of times the scanning lines on televisions and computer monitors ‘refresh’ themselves in one second.
Most people with photosensitive epilepsy are sensitive to 16-25 Hz. Some people may be sensitive to rates as low as 3 Hz and as high as 60 Hz.
Diagnosing photosensitive epilepsy
If you have an epileptic seizure when looking at flashing or flickering lights or certain patterns, this is a sign that you may have photosensitive epilepsy.
Your doctor may ask you to have an electroencephalogram (EEG) test. This test records the electrical signals from your brain on an EEG machine. During the test, you will be asked to look at some flashing lights. If doing this changes the electrical signals in your brain, it may indicate that you have photosensitive epilepsy.
The person doing the test will usually try to stop the test before you actually have a seizure. However, there is a small risk that you will have a seizure when the test is done.
Epilepsy Action has more information about EEG tests and diagnosing epilepsy.
Ways to reduce the risk of seizures if you have photosensitive epilepsy
- Avoid looking at anything that you know may trigger a seizure.
- Avoid things that can increase your risk of having a seizure. These can include feeling tired or stressed, not having enough sleep and drinking alcohol.
- If you take epilepsy medicine, always take it as prescribed by your doctor.
- If you look at something that might trigger a seizure, don’t close your eyes. This could increase your risk of having a seizure. Instead, immediately cover one eye with the palm of your hand and turn away from the trigger. This reduces the number of brain cells that are stimulated and reduces the risk of a seizure happening.
Epilepsy Action would like to thank Professor G F A Harding, Emeritus Professor of Clinical Neurophysiology, Aston University and also Professor Stefano Seri, Professor of Clinical Neurophysiology at Aston University and Consultant at the Birmingham Children’s Hospital NHS Foundation Trust for their contribution to this information.
This information has been produced under the terms of The Information Standard.
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Updated March 2012To be reviewed March 2015
Comments: read the 29 comments or add yours
Comments
I have epilepsy but I'm not sure if its photosensitive. I will soon be taking on a career as a police officer and will have to drive a car with strobes on it. See the problem here? I have always somewhat suspected I was photosensitive but I want to know if it would be OK for me to turn on my old strobe at home and have a go at it for about 5 or 10 minutes to see if there's is any effect?
Hi. Only about three in every hundred people who have epilepsy, have photosensitive epilepsy. You would normally be told this when you are diagnosed. The EEG, which is routinely used in diagnosis, usually involves specifically testing for photosensitive epilepsy. So it is reasonably likely that you would already have been told, or already realised you had photosensitive epilepsy.
If you’re not sure, you could always check with your doctor or epilepsy nurse. This is a more advisable course of action than experimenting by yourself. I am assuming you currently have a driving licence. If you were to ‘test’ yourself and you had a seizure you would lose your driving licence.
Also there is a particular flash or flicker rate which is most likely to trigger seizures in people with photosensitive epilepsy, so the police siren may well not be within that range.
I hope the career goes well.
Cherry
Advice and Information Team
Hi my daughter is 8 months and started having seizures aged 2 days. She was retrospectively diagnosed with benign neonatal seizures and put on medication. She had been seizure free for 7 months and fully off all meds after 5 months (so 3 months off meds) she then had a seizure when we put xmas lights up :-(
She has only had one episode (although we haven't had lights on since) but she was down with tree lights all day (other than nap times) and had the seizure when I took her up for her bath.
She is going to have another eeg with light stimulation but my question is do some sufferer have to have prolongep exposure to a cause before having a seizure and others can have co instant seizure?
Thank you for any advice I am currently back to being very worried as thought she had grown out of the seizures
Dear Kate,
Sorry to hear about your worries over your daughter. Photosensitive epilepsy is when someone’s seizures are triggered by lights flashing at a certain frequency. Normally if this is the way your seizures are triggered, the seizure would happen very quickly after the trigger. By this I mean seconds, or a minute or two at most. So the seizures could have been coincidental.
Hopefully the EEG will show more clearly if your daughter has photosensitive epilepsy.
It is no surprise as a mum that you are worried. If it would help to link up with other parents and carers of people with epilepsy, you may be interested in our online community,forum4e. Hope this helps.
Cherry
Advice and Information Team
Hi, i am a 45 years old woman who never had any epilepsy crisis, but today aften seing flashing lights of an emergency vehicle I felt really strange, couldnt see propoerly with aura, felt dizzy and like absent. I wonder if it is some kind of epilepsy. When I was a teenager I suffered from migraines with aura.
hi, my 14 year daughter has been diagnosed with photosensitivity epilepsy. is it safe for her to go to the cinema?
Hi Tammy
Generally going to the cinema isn’t a risk . However, some films do have flashing or flickering lights, which could trigger a seizure in people with photosensitive epilepsy.
The British Board of Film Classification (BBFC) say that the film makers and those who distribute them should identify films that may contain flashing lights. They should then make sure that warnings are given to viewers about this. However, there is no guarantee that this will always happen. So, before your daughter goes to see a particular film she could make some enquiries about it, with the BBFC.
I hope this helps.
Rosanna
Advice and Information Team
i have a question the doctors say i have photosynthesis epilepsy but they said EEG doesn't show any thing wrong but every time there are flashing lights i am said to have a tonic clonic episode but i also shake like im very cold and the nurse at my school says its just anxiety im kinda confused what is wrong ?
Hi Kristen. This is a bit tricky to give a short answer to. Photosensitive epilepsy is quite specific. And it may be you’re anxious about seizures, which would be understandable. I’m not surprised you’re confused either. If you wanted to ring us on the Epilepsy Freephone helpline 0808 800 5050, we could talk about it a bit more.
Cherry
Advice and Information Team
Hi, I experienced similar to you in fluorescent light. My arms shook until they were numb and once leaving the light they stopped. I was given an EEG some years ago to see if I had epilepsy, the test said I had not. I remember the room was lit in fluorescent light through out the test. If the test is supposed to show a change in state of the brain with the trigger then the light being present throughout would only show one state? Sometimes it feels like an absense seizure if exposed for a moment. If left in the light it feels like my brain is being constantly attacked, not at all like the thump thump rhythmic way a migraine does. So far doctors say its eye strain. Just feels a little extreme to be eye strain, and not as extreme as epilepsy. When it happens I still feel partly in control. Takes me a day to recover from being in that light usually. Distressing and frustrating since all energy saving lights emit this type of light, except LED.
Please do not take this the wrong way. With having PSE I am so sick and tired of the recommendation of looking away and/covering one eye. There are times I do not see the reflection, flashing light, commercial with quick picture I time to look away or cover an eye. My body is quickly shacking and it need to get away from stimulus
Hi, I seem to be having a lot of possible clonic or myoclonic seizures around fluorescent or strobing lights. I don't loose consciousness, but I do fall on the floor and my whole body goes into convulsions. Other times, only my arms, face and shoulders react. About two weeks ago, one whole-body seizure went on for 15 minutes, until finally someone found the light switch, and turned off the fluorescent lights - the seizure stopped 3 minutes later. I'm supposed to get an EEG and MRI sometime, but I don't know when - it could be months. I'm afraid to go anywhere with fluorescent lights because I don't want to destroy whatever is left of my brain, and they are happening with great frequency around any kind of strobing lights. Do you know if it is safe to go grocery shopping, or do these seizures cause brain damage? I can't drive anyway, because I also have dystonia and dyskinesia (so their existence does not matter if they aren't causing damage). I used to be able to stop them by wearing an eye patch over one eye, but now I have to cover both eyes to get it to stop.
Also, should one go to the emergency room if a seizure goes on for a long time, but has stopped?
Thank you so much :)
Hi Su
That sounds very scary. It’s difficult to know what to suggest, as covering one eye should stop your brain being sensitive to
flashing or flickering lights. Having said that, fluorescent lights shouldn’t actually trigger seizures, as they don’t flicker unless they are faulty.
To our understanding, seizures are most likely to cause brain damage if they turn into status-epilepticus. You don’t usually need to go to the emergency room if your seizures have stopped, unless you have injured yourself. But it might be useful to get some advice from your epilepsy specialist, particularly as your seizure pattern has changed. They might be able to get you an earlier appointment for your EEG/MRI scan.
Kathy
Advice and Information Team
I was diagnosed with epilepsy at age 3. I had grand mal seizures and would black out for a few minutes and stop breathing. I have out grown my seizures and have been seizure free for 29 years. earlier this year i became HIGHLY sensitive to flashing lights, the lines on the interstate and have frequent headaches. Could my epilepsy be coming back?
Hi Teresa
Thank you for your question.
Epilepsy is an unpredictable condition. Unfortunately, for some people their epilepsy can return many years after their last seizure.
There are a number of medical conditions that can cause symptoms similar to epilepsy. For this reason, and the fact we aren’t medically qualified, we can’t say if your symptoms are epilepsy or not. If you haven’t already, it would be advisable to talk to your family doctor. If necessary they will refer you back to a neurologist.
It would also be helpful for the doctors if you keep a diary of your symptoms.
If we can be of any more help, please feel free to contact us again, either by email or the Epilepsy Helpline freephone 0808 800 5050.
Diane Wallace
Advice and Information Team
Back in the 1960s i would be about 6 years old we had a large black & white tv with a ratchet type dial to change channels,i would change the channels whilst staring into the screen or turn up the brightness till the screen was white which then caused me to have a seizure.I had EEG tests and my mum was told i had an active brain ? The doctor said i would grow out of them as i got older,with medication i stopped going near the tv,i had my last seizure in my 30s but i am still taking 1 epilim a day.I have found not getting enough sleep along with having a bit too much to drink can cause my body to have jerks when i first get up but not having enough sleep is the main issue.
Hi everyone. My teenage daughter has several types of epilepsy including photosensitive fits which are triggered by lighting, screens, and even sunlight reflecting off of passing cars. She has found strong black glasses with large side frames very useful - they don't stop the fits but they do lessen them. She is on a very high dose of medication but still fits. She does find that some major high street shops with anti-shoplifting lighting here in the UK give her real problems and we find that we are having to keep her out of some these altogether.
Th strobe light on the iPhone gave my 14 year old Doberman a violent seizure.
Hi Chantel.
Thank you for this information. It must have been a distressing experience for you and your dog. We will look at the impact of phone apps when reviewing our information on photosensitive epilepsy.
Kind regards
Vicky
Advice & Information Team
Hi,
I am at the age of 17 and I have been having what it seems like as epilepsy, but every time I have an EEG done it comes out normal. Symptoms include, jerking of the muscles, loss of consciousness, falling down, blurred vision, lightheadedness, confusion, head pounding, and dizziness. I only get these when I am watching TV, playing video games, watching people play at the park, and watching computer screens. Are these signs of having photosensitive epilepsy? Is it common for the EEG to come out normal?
Michael,
We have responded to you by email.
Regards
Diane Wallace
Advice and Information Team
Hi, I work for a company who do bathroom adaptations. I have a client who suffers from seizure's (I am not sure if he is a photosensitive epileptic sufferer, as the report said at the top that it is only 3 in a 100 that are) When he goes into the bathroom he walks in backwards because he doesn't like the light flickering on. Do you know if there are any bathroom light units that are up to current regs? (IP44 standard unit)
regards Jo
Hi Jo
People who have photosensitive epilepsy might have a seizure triggered by a fluorescent strip light or light bulb if it flickers because it is faulty. Otherwise, they should not cause a problem.
If your client does not have photosensitive epilepsy, there is no reason why any kind of lighting would cause him to have a seizure. Some people find different types off lighting uncomfortable, but this is not necessarily for any reason related to epilepsy.
We don’t have any information about any bathroom light units.
I hope that helps.
Amanda
Advice and Information Team
Thank you for your prompt reply. Yes that does help, I am going to discuss this with his occupational therapist.
Hi Jo,
You could try to replace them with LED light bulbs, they don't flicker and have a very balanced light intensity output. Failing that there are lighting specialists that can check levels and advise appropriately
My daughter is worried about having her photo taken for her free travel pass as she often experiences her pre tonic clonic aura in flashing & bright light, although she is on a very high dosage of two different medicines which have kept her seizure free for just over 12 months. Is it safe for her to have her photo taken? She is just beginning to get her confidence back so we could do without any setbacks. She had her first seizure whilst travelling alone on a bus so it is encouraging that she should even be contemplating obtaining a travel pass.
Hi Kathryn
I’m sorry to have to tell you this, but if your daughter has been seizure-free for 12 months, then she won’t be entitled to a free bus pass. This is because she would be able to apply for a driving licence now.
Just to answer your question anyway, if your daughter has been diagnosed with photosensitive epilepsy then she would have a problem with lights that flash at a certain frequency. So a single flash should be absolutely fine.
Cherry
Advice and Information Team
Bus pass information: https://www.epilepsy.org.uk/info/benefits/england#free-bus-fares
Photosensitive epilepsy: https://www.epilepsy.org.uk/info/photosensitive-epilepsy
Did I forget to mention that my daughter is also visually impaired as a result of the brain haemorrhage which also caused her epilepsy? She will never be allowed to drive!! Back to my question....
Hi Kathryn
If your daughter has been diagnosed with photosensitive epilepsy then she would have a problem with lights that flash at a certain frequency. So a single flash should be fine.
And whilst we can never be certain, I can reassure you that we have never had any reports of someone having a seizure triggered by having their photograph taken.
Thank you.
Cherry
Advice and Information Team