Disclosed is a method of preparing an operation of surfacing of a lens blank to transform the lens blank into a generated lens having a predetermined prism corresponding to an inclination between a front surface and a back surface of the generated lens at least locally. The method includes: for a plurality of devices destined to interact with the lens blank during the operation of surfacing to manufacture the predetermined prism of the generated lens, attributing a priority order to each; based on the priority order, attributing to each device a prism portion which is zero or included in a respective range delimited by a respective minimum prism portion and a respective maximum prism portion, the prism portion representing contribution of the corresponding device to the prism of the generated lens, for further interaction of each device with the lens blank during the operation of surfacing.