A method, implemented using a processing module, comprising: - acquiring prescription data including at least a sphere value, a cylinder value and an addition value; - generating virtual surface data of a progressive addition lens for a further operation of surfacing of a lens blank, said operation of surfacing being configured to transform the lens blank into a surfaced lens satisfying the prescription data, said generating virtual surface data comprising: • selecting a virtual base surface having a default addition value in a virtual base surface database storing at least one virtual progressive base surface, said selection being independent of the prescribed addition value; • processing the selected virtual base surface according to the prescribed addition value to obtain a modified virtual base surface providing at least a part of the prescribed addition value; • selecting a virtual adjusting surface in a virtual adjusting surface database storing a plurality of virtual adjusting surfaces at least on the basis of a value of a parameter relative to the modified virtual base surface; • combining the modified virtual base surface and the selected virtual adjusting surface to form a virtual progressive adjusted surface; and using said virtual progressive adjusted surface for generating said virtual surface data; and - selecting a semi-finished lens in a semi-finished lens database on the basis of the prescribed sphere value and the prescribed cylinder value, said semi-finished lens having a finished surface and an unfinished surface and being destined to a further operation of surfacing of the unfinished surface on the basis of the virtual generated surface data. - acquiring prescription data including at least a sphere value, a cylinder value and an addition value; - generating virtual surface data of a progressive addition lens for a further operation of surfacing of a lens blank, said operation of surfacing being configured to transform the lens blank into a surfaced lens satisfying the prescription data, said generating virtual surface data comprising: • selecting a virtual base surface having a default addition value in a virtual base surface database storing at least one virtual progressive base surface, said selection being independent of the prescribed addition value; • processing the selected virtual base surface according to the prescribed addition value to obtain a modified virtual base surface providing at least a part of the prescribed addition value; • selecting a virtual adjusting surface in a virtual adjusting surface database storing a plurality of virtual adjusting surfaces at least on the basis of a value of a parameter relative to the modified virtual base surface; • combining the modified virtual base surface and the selected virtual adjusting surface to form a virtual progressive adjusted surface; and using said virtual progressive adjusted surface for generating said virtual surface data; and • selecting a virtual base surface having a default addition value in a virtual base surface database storing at least one virtual progressive base surface, said selection being independent of the prescribed addition value; • processing the selected virtual base surface according to the prescribed addition value to obtain a modified virtual base surface providing at least a part of the prescribed addition value; • selecting a virtual adjusting surface in a virtual adjusting surface database storing a plurality of virtual adjusting surfaces at least on the basis of a value of a parameter relative to the modified virtual base surface; • combining the modified virtual base surface and the selected virtual adjusting surface to form a virtual progressive adjusted surface; and using said virtual progressive adjusted surface for generating said virtual surface data; and - selecting a semi-finished lens in a semi-finished lens database on the basis of the prescribed sphere value and the prescribed cylinder value, said semi-finished lens having a finished surface and an unfinished surface and being destined to a further operation of surfacing of the unfinished surface on the basis of the virtual generated surface data.