Abstract: A fastener, particularly for lenses, has an elastically deformable elongated body that is suitable to be inserted in through holes formed in one of the members to be joined; the elongated body comprises a substantially cylindrical stem that has a first end that forms a wider head and a second end that forms a plurality of frustum-shaped members that are arranged in series; the bases of the frustum-shaped members are directed towards the wider head the second end terminates into an extension, the diameter of the wide head and the diameter of the bases are greater than the diameter of the stem.