The invention relates to optical glasses intended for the application fields of imaging, sensors, microscopy, medical technology, digital projection, photolithography, laser technology, waferchip technology, and for telecommunication, optical communication engineering and opticslighting in the automotive sector, having a refractive index of 1. In a preferred embodiment the hand tool comprises a set of hand operated pliers that are adapted to have, removably attached to them, replaceable jaws which are connected to handles by means of connectors which are in turn, adapted to be actuated by an actuating member of a retooling device. The opposite edge has a second radius and is parallel to and approximately the length of the first hone edge.