NC grinding process for the circumferential edge and top facet of an ophthalmic lens

PCT No. PCT/EP95/01882 Sec. 371 Date Nov. 19, 1996 Sec. 102(e) Date Nov. 19, 1996 PCT Filed May 17, 1995 PCT Pub. No. WO95/32075 PCT Pub. Date Nov. 30, 1995A method for N-C controlled grinding of the top facet of an ophthalmic lens comprising: determining the length of a circumference of an apex of a facet groove in a lens mount which will receive the lens, determining the length of the circumference of the apex of the top facet in the vicinity of the circumferential edge which is to be installed in the lens mount, comparing those lengths and determining whether the deviation in the length of the facet groove from the length of the top facet is within a preset limit. If it is not within the limit, changing the position of the Lop facet to be within the limit, determining a change value and then finish grinding the top facet using values selected from the comparison value or the change value. The data concerning the shape of the lens mount and of the optometric data of the lens wearer may be entered in the computer