The nurse working in a preoperative unit was caring for a patient with a cataract and observed an order of the eye drops Atropine OS, every hour. What do you mean by OS?

Correct option is C

In medical terminology, "OS" stands for oculus sinister, which refers to the left eye. It is part of standard abbreviations used in prescriptions for ophthalmic medications. "OD" stands for right eye (oculus dexter), and "OU" means both eyes. Understanding these abbreviations is critical for safe and correct medication administration.
Explanation of options: (a) Right eye – This is denoted by "OD" not "OS". (b) Both eye – Represented by "OU" (oculus uterque). (c) Left eye – Correct interpretation of "OS" (oculus sinister). (d) Unaffected eye – This term is descriptive, not a standard abbreviation.