This standard specifies the conditions and recommended methods for testing the performance of a binocular stereo head microscope (hereinafter referred to as a stereo microscope) that has independent left and right imaging optical systems and is capable of stereoscopic observation. However, it is not applicable to surgical microscopes.
JIS B 7139-2:2008 Referenced Document
JIS B 7139-1 Stereomicroscopes -- Part 1: Minimum requirements for stereomicroscopes