Photogenic epilepsy - when light triggers an epileptic seizure
Photogenic epilepsy - when light triggers an epileptic seizure
Epilepsy can be triggered by many different external factors. These include auditory, sensory, taste-smell, or visual stimuli. The latter cause photogenic epilepsy, also known as light-sensitive or photosensitive epilepsy.
What is photogenic epilepsy and what can trigger its seizures?
Photogenic epilepsy, affecting one in 4,000 people, is a special type of epilepsy characterized by sensitivity to light stimuli that trigger seizures. It is recurrent but can be controlled with appropriate pharmacotherapy. It's worth noting that these light stimuli are risk factors rather than constant and certain causes of seizures. The same circumstances may provoke unwanted behaviors in one case but remain completely neutral for the patient in another.
What factors can trigger a photogenic epilepsy seizure?
- strobe lights
- regularly flickering light appearing, for example, while driving when alternating between sunlight and shade from passing trees
- bright lighting
- rapid eye blinking
- computer games
- television
- sun reflections appearing on rippling water
- specific geometric patterns, such as a black and white checkerboard
- eyes moving across black letters contrasting with white background while reading (so-called reading epilepsy)
What types of seizures does photogenic epilepsy cause?
Photogenic reflex epilepsy results in two types of seizures: generalized tonic-clonic (IIE) and myoclonic (IIB)
Tonic-clonic seizures are considered the most characteristic type of symptoms. They begin with a sudden contraction of all muscles, causing the patient to lose balance and fall. Sometimes they bite their tongue, and their face turns blue. In the next phase, convulsions appear, and saliva is secreted from the patient's mouth. Such a seizure typically lasts from two to three minutes.
Myoclonic seizures are characterized by sudden, involuntary muscle jerks, sometimes of the entire body. As a result, patients experience violent movements like straightening their arms or conversely - bending them at the elbows. Sometimes patients fall to the floor or drop objects from their hands.
Programs triggering epilepsy seizures
Photogenic epilepsy can appear in previously completely healthy people, for example while watching television. In Japan in 1997, an episode of Pokemon anime was aired. The repetitive visual effects it contained triggered epilepsy seizures in a significant number of viewers. As many as 685 children were hospitalized. For most patients, this was their first epileptic seizure in life.
A similar situation occurred on British television. A Citroen advertisement that aired contained the word "yes" which appeared on screen 304 times, flashing at a very rapid pace while changing colors. After epilepsy seizures were reported, the decision was made to withdraw the commercial from television.
To avoid such incidents, many countries worldwide - including Poland - have introduced mandatory screening of materials intended for broadcast for their potential photogenicity. The analysis is performed using the Harding test created by Professor Graham Harding - a specialist in photosensitive epilepsy.
Photogenic epilepsy - can seizures be prevented?
Dealing with this type of epilepsy can be burdensome for the patient, but it doesn't mean they have to give up watching television, working at a computer, walking in full sunlight, or other outdoor activities.
Besides pharmacotherapy prescribed by a doctor, it's also important to remember to try to minimize light stimulation.
When going outside or using screens, one should wear polarized sunglasses that block glare and maintain natural color appearance. Patients watching television or using computers should ensure the room is well lit to minimize contrast between the interior and screen. They should also avoid viewing the monitor from close up - equipment must be placed at a distance 3 or even 4 times greater than its inch size. It's also recommended to place a lamp behind the screen.