3D films and virtual reality
Photosensitive epilepsy affects up to 3% of people with epilepsy. This is where seizures are triggered by certain rates of flashing images or light. For most people seeing a film at the cinema is unlikely to trigger seizures. However, many films these days are released in 3D. Also Virtual Reality (VR) is a technology that is being used more and more in everyday life. So what are the risks for people with photosensitive epilepsy?
There are relatively few cases of cinema films triggering photosensitive seizures. Normal cinema films show 24 frames per second, which would produce a flash rate that could be be a risk to people with photosensitive epilepsy. However, the brightness of the images in the cinema is very low (about one hundredth of a television set). So this reduces the risk.
With 3D films, three images are projected, at 48 flashes per second. Because the images are polarised (aimed at each separate eye) that is 24 flashes per second to each eye. This reduces the effect by half - to the same flash rate as a normal cinema film. So the risk of a 3D film triggering a seizure is about the same as a normal cinema film.
Because epilepsy is so individual your own neurologist may be able to give you information that is specific to you.
Virtual Reality (VR) is an experience created by a computer. It stimulates a number of senses and can seem like you are actually experiencing what the computer is generating. It has been used for training for quite a long time (eg pilots and surgeons) and is becoming increasingly popular. So, how might VR affect people with photosensitive epilepsy?
With VR the images flash very quickly and generally this is too quickly to trigger a seizure in people with photosensitive epilepsy. However, the field of view is large and so more of the eye is stimulated. This means that more of the brain may be affected and this may trigger a photosensitive seizure.
Again, your own neurologist may be able to give you information that is specific to you.
We are grateful to Professor Stefano Seri MD, FRCP Professor of Clinical Neurophysiology, School of Life and Health Sciences, Aston University for his guidance on this information.
Information reviewed May 2019
Around 1 in 100 people has epilepsy and of these people, around 3% have photosensitive epilepsy. This is when seizures are triggered by certain rates of flashing lights or contrasting light and dark patterns.
Triggers are situations that can bring on a seizure in some people with epilepsy.
There are many different types of epileptic seizure. Any of us could potentially have a single epileptic seizure at some point in our lives. This is not the same as having epilepsy, which is a tendency to have seizures that start in the brain.
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