What does the abbreviation 'OS' refer to in healthcare?

In healthcare, the abbreviation 'OS' stands for "oculus sinister," which is Latin for "left eye." This terminology is commonly used in ophthalmology and other medical fields to specify the left eye when discussing conditions, prescriptions, or treatments. The use of Latin abbreviations like 'OS' helps standardize communication among healthcare professionals, ensuring clarity and consistency in patient care.

In contrast, other abbreviations related to eye care use similar Latin terms, but refer to different anatomical features. The term for the right eye is 'OD,' which stands for "oculus dexter." The choice of 'OS' indicates the precise focus on the left eye specifically, making it the correct answer in this context.