What does the abbreviation "o" refer to in a prescription?

The abbreviation "o" in a prescription context typically refers to "oculus," which is Latin for "eye." This designation is significant in pharmaceuticals and optometry, as it is used to indicate that a medication should be applied to or around the eye. Understanding this abbreviation is crucial for ensuring that medications are administered correctly, especially since eye treatments often differ significantly from those intended for other parts of the body, like the ears or skin.

In contrast, other abbreviations for prescription use include “a” or “d” for right or both, which helps differentiate directions in prescribing for various conditions. The specific use of "o" for the eye underscores the importance of precise language in medical prescriptions to ensure patient safety and proper treatment.