What does "OS" stand for in optical prescriptions?

In optical prescriptions, "OS" is an abbreviation derived from the Latin term "oculus sinister," which translates to "left eye." This designation is commonly used by eye care professionals to specify the measurements or prescription details pertaining to the patient's left eye. Understanding these abbreviations is crucial for interpreting prescriptions accurately, as each eye typically has different visual needs that must be addressed with specific corrective measures.

The other options refer to different concepts regarding eye prescriptions. "Both eyes" would typically be indicated as "OU" (oculus uterque), while "Right eye" is denoted by "OD" (oculus dexter). "Eye examination" does not correspond to a specific eye reference but rather pertains to the overall assessment process of a patient's ocular health. This underscores the importance of familiarizing oneself with the terminology associated with optical prescriptions in order to provide effective eye care.