The flashing light device consists of a Photic light or also can be called flash light where intensity, frequency and duration of the emitted light are operator controlled. The Flash light is positioned about a meter distance from the patient head and usually flash light is not given continuously when frequency is changed as a pause for a certain time separates different flash light frequency values.
The Photic stimulation is usually used as a part of routine EEG test and can provoke seizure in certain percentage of patients.