OS stands for Left Eye (oculus sinister).
What does OS mean?
left eye
OS stands for left eye, from the Latin oculus sinister. It appears on prescriptions and eye notes to show that a finding or treatment applies to the left eye. It sits alongside OD (right eye) and OU (both eyes). Like the ear abbreviations, OS is on several do not use lists because it can be misread, and writing left eye in full is often recommended.
When is OS used?
OS appears in ophthalmology and optometry notes and on prescriptions for eye medication, alongside OD and OU.
Frequently asked questions
What does OS stand for?
OS stands for left eye, from the Latin oculus sinister.
How does OS relate to OD and OU?
OD means right eye and OU means both eyes, while OS means left eye.
Is OS safe to use?
OS is on several do not use lists because it can be misread. Writing left eye in full is safer.
Where is OS used?
It appears on eye prescriptions and notes to show a finding or treatment for the left eye.