In medical notation, what does OS refer to?

In medical notation, OS stands for "oculus sinister," which is Latin for "left eye." This term is commonly used by healthcare professionals when documenting information related to eye care or vision testing. The notation helps practitioners specify whether they are referring to the right eye, left eye, or both, which is crucial for accurate diagnosis and treatment.

In contrast, the term for the right eye is referred to as OD ("oculus dexter"), and binocular or both eyes together is denoted as OU ("oculus uterque"). Thus, the use of OS for the left eye is well established in medical contexts to ensure clear communication regarding ocular health.