Abstract: Apparatus for moving a tool such as a grinding wheel of a lens generating machine comprises a carrier for the tool which is movable about a pivot along an arcuate path and a cam and follower device operable to move the carrier along a slideway transverse to the arcuate path as a result of movement of the carrier about the pivot. In that way the tool can be controlled so that it follows a locus determined by the two movements.

Abstract: A method of forming a lens holder comprising mounting a support member in a lens-holding body, forming at least one contact surface on the support member, positioning a former on the contact surface such that a curved surface defined by the former engages the contact surface, introducing a settable mass of flowable material into a cavity between the curved surface and the lens-holding body, and removing the former from the contact surface after the material has set. The set material defines a surface for supporting a lens having a curved surface substantially corresponding to the curved surface to the former. A plurality of support members may be formed by the method of the invention on a single lens holder.