This tool includes: a rigid support (104) having a transverse end surface (113); an elastically compressible interface that is pressed against and covers the end surface; a flexible pad adapted to be pressed against the optical surface, itself pressed against and covering the interface on the opposite side of and in line with the end surface (113); spring return element (115) connecting the support (104) to a peripheral portion of the flexible pad situated transversely beyond the end surface (113); and a flexible flange (131) that is part of a base (130) to which the rigid support (104), which is surrounded by the flange (131), also belongs.
