Which abbreviation indicates the administration of medication to both eyes?

The abbreviation that indicates the administration of medication to both eyes is O.U., which stands for "oculus uterque" in Latin, meaning "both eyes." This term is commonly used in medical prescriptions and documentation to ensure that the medication is applied to both eyes as needed, particularly in scenarios involving eye drops or ocular treatments.

Understanding the abbreviations is crucial for healthcare providers to ensure accurate medication administration. O.S. is used specifically for the left eye, while B.I. generally refers to "both ears," not eyes. B.O. is not a standard abbreviation in this context, as it does not directly refer to ocular administration. Hence, O.U. is the correct choice for indicating both eyes in medication administration.