What does "OU" mean when referring to prescription instructions?

The abbreviation "OU" comes from the Latin term "oculus uterque," which translates to "both eyes." In prescription instructions, when a healthcare provider instructs a patient to use a medication in "OU," they are indicating that the treatment should be applied to both eyes. This is commonly seen with ophthalmic medications, such as eye drops, where it may be necessary to treat both eyes simultaneously. Understanding this terminology is essential for correctly interpreting prescriptions and ensuring patient safety in pharmaceutical practices.