Photosensitive seizure

A very small percentage of people may experience a seizure when exposed to certain visual images, including flashing lights or patterns that may appear in video games. Even people who have no history of seizures or epilepsy may have an undiagnosed condition that can cause these “photosensitive epileptic seizures” while watching video games.
These seizures may have a variety of symptoms, including lightheadedness, altered vision, eye or face twitching, jerking or shaking of arms or legs, disorientation, confusion, or momentary loss of awareness. Seizures may also cause loss of consciousness or convulsions that can lead to injury from falling down or striking nearby objects.
Immediately stop playing and consult a doctor if you experience any of these symptoms. Parents should watch for or ask their children about the above symptoms - children and teenagers are more likely than adults to experience these seizures.
The risk of photosensitive epileptic seizures may be reduced by taking the following precautions: · Play in a well-lit room · Do not play if you are drowsy or fatigued If you or any of your relatives have a history of seizures or epilepsy, consult a doctor before playing.
More Symptoms
Persons with PSE experience epileptiform seizures upon exposure to certain visual stimuli. The exact nature of the stimulus or stimuli that triggers the seizures varies from one patient to another, as does the nature and severity of the resulting seizures (ranging from brief absence seizures to full tonic-clonic seizures). Many PSE patients experience an “aura” or feel odd sensations before the seizure occurs, and this can serve as a warning to a patient to move away from the trigger stimulus.
The visual trigger for a seizure is generally cyclic, forming a regular pattern in time or space. Flashing lights or rapidly changing or alternating images (as in clubs, around emergency vehicles, in action movies or television programs, etc.) are an example of patterns in time that can trigger seizures, and these are the most common triggers. Static spatial patterns such as stripes and squares may trigger seizures as well, even if they do not move. In some cases, the trigger must be both spatially and temporally cyclic, such as a certain moving pattern of bars.
Several characteristics are common in the trigger stimuli of many PSE patients. The patterns are usually high in luminance contrast (bright flashes of light alternating with darkness, or white bars against a black background). Contrasts in color alone (without changes in luminance) are rarely triggers for PSE. Some patients are more affected by patterns of certain colors than by patterns of other colors. The exact spacing of a pattern in time or space is important and varies from one individual to another: a patient may readily experience seizures when exposed to lights that flash seven times per second, but may be unaffected by lights that flash twice per second or twenty times per second. Stimuli that fill the entire visual field are more likely to cause seizures than those that appear in only a portion of the visual field. Stimuli perceived with both eyes are usually much more likely to cause seizures than stimuli seen with one eye only (which is why covering one eye may allow patients to avoid seizures when presented with visual challenges). Some patients are more sensitive with their eyes closed; others are more sensitive with their eyes open.
Sensitivity is increased by alcohol consumption, sleep deprivation, and other forms of stress