Abstract: The invention relates to a shadowless lighting appliance more particularly pplicable for illuminating areas exposed for surgery in operating theatres. A lighting appliance according to this invention is characterized by the fact that it includes at least the following combination of means: - a light source; - a reflecting surface of revolution and - a glass formed of dioptric radial elements, the function of each element being to provide, by refraction to either side of a radial plane, the spreading of a beam of light reflected by a portion of said reflecting surface proximate a generatrix thereof, such that the elemental patch of light obtained on a plane be a luminous quadrilateral. In one form of embodiment, the above combination of means further includes a sleeve consisting of an optical system surrounding the light source.