OD and OS are abbreviations used in eye prescriptions to denote the right and left eyes, respectively. They are Latin acronyms: OD stands for oculus dextrus (right eye), and OS stands for oculus sinister (left eye).
Understanding OD and OS
When reviewing your eyeglass or contact lens prescription, you’ll likely see these abbreviations. Here's a breakdown of what they mean:
| Abbreviation | Latin Term | Meaning |
|---|---|---|
| OD | oculus dextrus | Right Eye |
| OS | oculus sinister | Left Eye |
Sometimes, you might also see the abbreviation OU, which stands for *oculus uterque* and means both eyes.
Here's why these terms are important:
- Prescription Clarity: Using OD and OS ensures there is no confusion about which lens parameters apply to which eye, as each eye may have a different correction prescription.
- Avoiding Errors: Accurate use of OD and OS prevents incorrect lens fitting and ensures optimal vision correction.
- Medical Communication: Eye care professionals use these terms as standard communication for clear records and continuity of care.
Example
Let's consider an example. If a prescription reads:
- OD: -2.00 -0.75 x 180
- OS: -1.50 -0.50 x 175
This means:
- The right eye (OD) has a spherical correction of -2.00, a cylindrical correction of -0.75, and an axis of 180 degrees.
- The left eye (OS) has a spherical correction of -1.50, a cylindrical correction of -0.50, and an axis of 175 degrees.
Therefore, understanding the difference between OD and OS is crucial for interpreting eye prescriptions accurately.
