Not that we use strobes that much, but each time we do, we ensure there is a warning notice in the programme & notices on all entrances & in the Box Office.
"Strobe lighting effects will be used during this performance. Patrons that may suffer from epilepsy & other visual light stimulation effects. Are advised to contact the Front of house staff, prior to entering the auditorium!"
In a lot of instances punters who are pre warned, can take appropriate action to reduce the possibility of a seizure.
However it is not only Strobe lighting, but other types such as coloured stripes & moving patterns can be a problem.
I have a particular problem with mercury vapour lighting, as I have survived 5 strokes thus far.
If I'm forewarned I can look away & cover my eyes or in extreme cases, use sunglasses, which help.
Seizures can be provoked by intermittent light and by patterns, most notably of stripes, whether flickering or steadily illuminated, static or moving. Sensitivity is usually, but not invariably, maximal at flicker rates of 20 Hz, and the majority of patients are sensitive within a flicker frequency range of 850 Hz. The range of sensitivity can be greater: occasionally patients are sensitive to isolated flashes or to flicker that is so rapid as to be almost imperceptible. The patterns to which patients are most sensitive are spatially periodic: one cycle of the pattern subtending about one third of a degree at the eye (spatial frequency, 3 cycles per degree). If the pattern drifts continuously in one direction, very few patients are sensitive, but if the pattern moves with a similar retinal velocity, repeatedly alternating its direction of motion, the susceptibility can be as high as that for flicker, with similar frequency dependence as regards the temporal periodicity. Overall, sensitivity to visual stimuli increases with the total amount of retina and thus visual cortex being stimulated.
------------- [western] Gondawandaland
"Hear the light & see the sound!
TOI TOI CHOOKAS
{may you always play to a full house!}
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