A method and a safety device for the protection of a user's eye, or other radiation sensitive system, from a pulsed radiation emitted by a radiation source by means of an electro-optical shutter used in conjunction with the radiation source. The electro-optical sutter defines the field of view of the user or of the system and is capable of being switched by an electrical voltage signal from a transparent state to an opaque state within a response time .DELTA.t.sub.r. The method comprises applying to the electro-optical shutter the electrical voltage signal at an operational time interval .DELTA.t.sub.o, prior to the emission of each radiation pulse and keeping the electro-optical shutter in its opaque state until the radiation pulse is emitted. The operational time interval .DELTA.t.sub.o is at least slightly longer than the response time .DELTA.t.sub.r so that, by the time of emission of each radiation pulse, the electro-optical shutter is in its opaque state.