Which abbreviation in a contact lens prescription represents the left eye?

In a contact lens prescription, the abbreviation that represents the left eye is "OS." This term is derived from the Latin phrase "oculus sinister," meaning "left eye." It is a standard notation used by eye care professionals to distinguish between the two eyes in prescriptions and medical documentation.

Understanding these abbreviations is crucial in ensuring accurate fitting and prescription of contact lenses, as using the correct designation for each eye prevents confusion and ensures that the patient receives the proper treatment for each specific eye condition.

The other abbreviations have specific meanings as well: "OD" refers to the right eye (from the Latin "oculus dexter"), "OU" signifies both eyes (from the Latin "oculus uterque"), and "RE" is less commonly used but often denotes the right eye. Recognizing these terms helps maintain clarity in communication within the optometric field.