A lighting device for illuminating an operative field comprises, in an axial lighting dome, a first ring of LEDs at a first color temperature, and a second ring of LEDs at a second color temperature different from said first color temperature, and an annular facetted mirror having semi-reflective facets and arranged about the same axis as said rings of LEDs. Collimation optical systems are provided between each ring of LEDs and the annular facetted mirror having semi-reflective facets. The annular facetted mirror having semi-reflective facets mixes the collimated light beams emitted by the two rings of LEDs coupled to the collimators, and forms first and second collimated resulting mixed light beams having the same intermediate color temperature. An annular facetted mirror having plane facets surrounds the annular facetted mirror having semi-reflective facets so as to reflect the first collimated resulting mixed light beam to combine it with said second collimated resulting mixed light beam in the operative field in a certain superposition configuration in a superposition plane in which an illumination spot is formed.
