Can a strobe light really cause a seizure?

[rostfrei]

I’ve always heard that a stobe light can cause a seizure in some people? If true, why?

[Duckster]

Epilepsy is a hidden episodic condition that affects more than 2.3 million Americans. For 5 percent (approximately 100,000) of people with epilepsy, exposure to flashing lights at certain intensities can trigger seizures. This condition is known as photosensitive epilepsy. It is more common in children and adolescents and becomes less frequent with age, with rare cases in the mid twenties.

Many people with epilepsy are unaware that they are sensitive to certain kinds of lights or flickering patterns until they have a seizure. Seizures in photosensitive people may be triggered by exposure to television screen flicker or rolling images, certain video games, computer monitors, alternating patterns of different colors, and the intense strobe lights in fire alarms. Also, some people have reported having seizures triggered by natural light, such as sunlight flickering through trees, light glancing off water or through the slats of Venetian blinds.

Not all televisions, video games, computer monitors and strobe lights trigger seizures, however. Factors that contribute to a photosensitive reaction are: the frequency of the flash (that is, how quickly the light is flashing), its brightness, the level of background lighting, the wavelength of the light and whether a person’s eyes are opened or closed. The frequency or speed of flashing light that is most likely to cause seizures varies from person to person. Generally, flashing light between the frequencies of 5 to 30 flashes per second (hertz) are most likely to trigger seizures.

Source: http://www.efa.org/answerplace/factsheets/photo.html