Which abbreviation indicates the left eye?

The abbreviation that indicates the left eye is "OS," which stands for "oculus sinister" in Latin. This term is commonly used in medical contexts to denote the left eye in prescriptions and medical records. Understanding eye abbreviations is crucial in ensuring accurate treatment and medication administration.

The other options represent different terms: "OU" means "oculus uterque," referring to both eyes, while "AD," which stands for "auris dextra," is used for the right ear. "BUCCAL" refers to the inner lining of the cheek, unrelated to eye terminology. Knowing these distinctions highlights the importance of precise language in pharmacology and healthcare.