What Is Photosensitive Epilepsy?

Photosensitive epilepsy (also known as PSE) is a form of reflex epilepsy in which seizures are triggered by an abnormal response to specific visual stimuli (such as flashing or flickering lights; bold patterns like polka dots; or regular moving patterns like the spinning blades of a ceiling fan). This is known as a photoparoxysmal response (PPR).

PSE is most common in children with genetic generalized epilepsy and certain syndromes like juvenile myoclonic epilepsy and Jeavons syndrome. It is more common in women and tends to diminish with age. It is also often preceded by an ‘aura’ or strange sensation right before the seizure occurs.

Photosensitive epileptic seizures are called generalized seizures because they can affect multiple areas of the brain. The most common seizures triggered by photosensitive epilepsy are tonic-clonic seizures. According to the National Library of Medicine, photosensitive epilepsy is quite rare, affecting between 2% and 14% of all people with epilepsy syndrome.

It’s worth noting that PSE is NOT the same as epilepsy syndrome. It is simply a kind of epilepsy that can occur in people who suffer from epilepsy syndrome, meaning patients can be epileptic and not suffer from photosensitive epilepsy.

What Types of Light Trigger a Photosensitive Epileptic Seizure?

When it comes to photosensitive epilepsy, the exact root cause of it is poorly understood. Studies do know there are plenty of triggers that seem to set it off, though. There are a variety of different lights that can trigger a photosensitive epileptic seizure, including:

  • Light emitted from TV, computer, cell phone, and movie screens
  • Flickering lights (strobe lights, faulty fluorescent bulbs, or disco lights), especially those that flash 15-25 times per second
  • High-contrast patterns and/or colors
  • Bright or reflected light, like sunlight off snow or a mirror
  • Columns of light passing through blinds or curtains

Other triggers include moving objects such as celling fans, propellers, and escalators. Factors such as tiredness, stress, and excitement can also be contributing causes.

Unlikely Triggers

The good news is, not ALL light triggers photosensitive epilepsy. While triggers vary from person to person, there are some light sources that don’t seem to cause issues. They include:

  • LCD screens
  • Interactive whiteboards
  • Lights that flash less than three times per second

What Are the Symptoms of a Photosensitive Epileptic Seizure?

Symptoms vary* from person to person, but they can include any of the following:

  • Dizziness
  • Vision changes
  • Headache
  • Out-of-body sensations
  • Jerky movement of your arms and legs
  • Nausea
  • Loss of consciousness
  • Uncontrollable muscle spasms
  • Falling
  • Clenching your teeth
  • Strange taste in mouth
  • Rapid eye movements
  • Loss of bladder control and bowel control

* (Source: Healthline - https://www.healthline.com/health/epilepsy/photosensitive-epilepsy#symptoms)

How long the seizure lasts depends on the frequency, type, and color of the triggering stimulus.

Here’s the thing. Many of the symptoms of photosensitive epilepsy are similar to those from plain old visual discomfort. So how do you tell the difference?

Differences Between Photosensitive Epilepsy and Visual Discomfort

It’s a matter of intensity. With everyday visual discomfort, as soon as you feel any symptoms, such as headache or dizziness, you can usually act preventatively and simply look away from the offending light source or trigger and the discomfort will disappear. With photosensitive epilepsy, however, once a seizure is triggered, you lose control of muscle function and thought process until the seizure is over. Essentially, once the body is triggered, there is no stopping the seizure until it runs its course. Which is why one the best ways to handle one is to try to prevent it from happening in the first place.

Medically, a doctor will be able to look at tests such as EEGs, and CT and MRI scans to diagnose whether a patient is suffering from photosensitive epilepsy and any other neurological issues that may be contributing to the seizures.

Methods and Treatment to Prevent Seizures from Photosensitive Epilepsy

The good news is that photosensitive epilepsy typically responds well to treatment, which may include antiepileptic drugs as well as non-pharmacological products, like tinted lenses. Additionally, the more patients can steer clear of triggers in the first place, the better.

Here are several helpful tips that can help you avoid photosensitive epileptic seizures:

  • Watch television in a well-lit room and from a distance where the screen doesn’t take up your entire field of vision.
  • Immediately cover one eye if you are exposed to a trigger.
  • Choose an LCD computer screen over a plasma one or another light tube-based screen.
  • Wear polarized sunglass outside and glasses fitted with lenses that have functional filters to help block out seizure-inducing light.
  • Avoid playing video games (or, if you do, check for seizure warnings).
  • Give your eyes regular breaks and close your eyes for a bit or step away from the screen.
  • Lower the brightness and contrast levels on your television and computer.

By minimizing exposure to potential triggers and using functional filters to filter out triggering types of light, patients can mitigate the discomfort associated with this type of epilepsy (and possibly even avoid them altogether).