What does the abbreviation "OS" refer to in medical terms?

In medical terminology, the abbreviation "OS" stands for "oculus sinister," which is Latin for "left eye." This term is commonly used in prescriptions and medical documentation to indicate which eye is being referred to, especially in relation to ocular conditions or treatments. Understanding this abbreviation is essential for healthcare professionals, as it aids in the accurate communication of patient care details concerning vision and eye health.

The other options refer to different anatomical locations: "Right ear" is indicated by "AD" (auris dextra), "Both ears" is often abbreviated as "AU" (auris uterque), and "Left ear" is abbreviated as "AS" (auris sinistra). These abbreviations are also significant in practice, but they are distinct from "OS," which specifically pertains to the left eye.