Method of calculating circumference and manufacturing a spectacle lens, circumference calculating device and circumference calculating program for use in producing a spectacle lens

摘要

There is provided a circumference calculating device including an expected shape specifying part 201b configured to obtain an expected finish shape of a bevel in consideration of an interference amount of a beveling tool when beveling is performed to an uncut spectacle lens; and a theoretical circumference calculating part 201d configured to obtain a bevel circumference of the spectacle lens having the expected finish shape obtained by the expected shape specifying part 201b, as a theoretical circumference of this spectacle lens.