nägemistaju muutlikkusmulje, mis on tingitud valgusstiimuli heleduse või spektraalkoostise pulsatsioonist, impression of unsteadiness of visual sensation induced by a light stimulus whose luminance or spectral distribution fluctuates with time, human-visible change in luminance of an illuminated surface or light source which can be due to fluctuations of the light source itself, or due to external causes such as due to rapid fluctuations in the voltage of the power supply (power-line flicker) or incompatibility with an external dimmer