A lighting device, which may be employed e.g. as a retrofit bulb for vehicle lamps, includes a light radiation source, e.g. a LED source, and a beam-narrowing optical system facing the light radiation source, for propagating a narrowed light radiation beam of the source along a longitudinal axis of the device. Arranged distally of the beam-narrowing optical system along the longitudinal axis, there is provided: a light reflector, a light-driving lens, a filament-like body including annular reflective surfaces extending around the longitudinal axis and exposed to light radiation from the light radiation source propagated through the light reflector and the light-driving lens, a distal mirror member having a reflective surface facing towards the filament-like body, to reflect light radiation towards annular reflective surfaces in the plurality of annular reflective surfaces. The light radiation reflected by the annular reflective surfaces of the filament-like body is spread radially from the longitudinal axis.