After the optometry routine labeling OD and OS is the English letters, OD indicates the right eye, OS indicates the left eye. Can also be written in Chinese as the right eye, left eye is relatively clear, this has nothing to do with the optometry data. Optometry data are expressed with DS or DC, DS indicates the degree of spherical lens, DC indicates the degree of column lens. After the DC also into an axial, that is, 180 degrees axis position so. So this is the formal optometry program, the way it is written, with OD for the right eye, OS for the left eye, there is no special meaning.