Flashing lights are one of the best-known causes of epileptic seizures - many people are aware that strobe lighting is a seizure trigger. However, while photosensitive epilepsy is well-known, it is actually quite rare. Around 3% to 5% of people with epilepsy have photosensitive seizures.
So, what is photosensitive epilepsy, what things trigger seizures, and how is it treated?
What is photosensitive epilepsy?
Photosensitive epilepsy is when your seizures are triggered by certain lights or patterns. The seizures usually happen when there is a high contrast between colors. This over stimulates certain parts of your brain, which can cause a seizure.
Related: What happens in your brain during a seizure?
If you have photosensitive epilepsy, it can cause many different kinds of seizures. However, tonic-clonic seizures are the most common.
Some people with photosensitive epilepsy only ever have seizures when they are exposed to flashing lights or contrasting patterns. But for other people, seizures can be triggered by other things too.
Who has photosensitive epilepsy?
Photosensitive epilepsy is fairly rare. It is more common in people who have juvenile myoclonic epilepsy, although it is associated with many other kinds of epilepsy syndrome too.
Most people start to develop photosensitive epilepsy between the ages of seven and 19, although it is possible to develop it later in life. Many people with photosensitive epilepsy notice that it affects them less as they get older.
Photosensitive epilepsy is more common in girls and women than it is among boys and men. However, boys with photosensitive epilepsy tend to have more seizures than girls because they play video games more often – and are therefore more exposed to this seizure trigger.
Learn more: Video games and seizure safety
Photosensitive epilepsy triggers
There are many things that can potentially trigger seizures if you have photosensitive epilepsy. These include:
Flashing lights are a well-known cause of epileptic seizures. It is most common if the lights flash between16 and 25 times per second - although some people are sensitive to slower flickering too.
Lighting that could cause seizures includes:
- Strobe lighting
- Older computer screens
- Video games
- Bicycle lights
- Older televisions
Learn more: Attending festivals, gigs and concerts with epilepsy
Some people’s photosensitive epilepsy is triggered by certain types of patterns. This is particularly common when they are looking at high contrast patterns with lots of alternating colors. Examples include:
- Posters with lots of stripes
- Big flags
- Some pieces of art
- Moving escalators
- Certain kinds of architecture
Sometimes people with photosensitive epilepsy notice their seizures are triggered when sunlight flickers on surfaces:
- Reflections on moving water
- Reflections on snow
- Light passing through blinds and tree leaves
- Light passing through trains or moving cars
Managing triggers if you have photosensitive epilepsy
If you know your seizures are triggered by light or patterns, avoiding situations where you’re exposed to these things can significantly reduce your seizure risk.
Speak to your doctor about managing the risks. They may recommend avoiding going to nightclubs (where strobe lighting is likely to be used), reducing the amount of time you spend playing video games and using up to date TV screens and monitors.
If you do find yourself in a situation where there are potential triggers, cover one eye with the palm of your hand and look away from the source of the light/pattern.
Some people find that photosensitive epilepsy glasses help if they know they are going to be in a situation where they could be exposed to triggers.
Diagnosis and treatment
To diagnose photosensitive epilepsy, a neurologist will use an EEG machine. They’ll monitor how your brain reacts when you are exposed to flashing lights.
If you have photosensitive epilepsy, your doctor will advise you on the most appropriate treatment path for you.
Living with photosensitive epilepsy
If you have photosensitive epilepsy, staying in control of your seizures is often perfectly possible by following some simple precautions and taking your anti-seizure medication. If you have any concerns about your seizures or seizure control, contact your epilepsy specialist.