OD and OS on an eye prescription are abbreviations for which eye each line refers to: OD is the right eye, OS is the left eye.

Quick Scoop: What is OD / OS in Eye Prescription?

Think of your prescription as a little map your optometrist writes for each eye separately.

  • OD = Oculus Dexter = right eye.
  • OS = Oculus Sinister = left eye.
  • You might also see OU = Oculus Uterque = both eyes.

Some modern prescriptions skip the Latin and just use RE / R (right eye) and LE / L (left eye).

Tiny example

If your prescription shows:

  • OD: -2.00
  • OS: -1.50

That simply means:

  • Right eye needs -2.00 power.
  • Left eye needs -1.50 power.

Mini HTML table (for clarity)

html

<table>
  <tr>
    <th>Code</th>
    <th>Latin term</th>
    <th>Meaning</th>
  </tr>
  <tr>
    <td>OD</td>
    <td>Oculus Dexter</td>
    <td>Right eye</td>
  </tr>
  <tr>
    <td>OS</td>
    <td>Oculus Sinister</td>
    <td>Left eye</td>
  </tr>
  <tr>
    <td>OU</td>
    <td>Oculus Uterque</td>
    <td>Both eyes</td>
  </tr>
</table>

In short, OD and OS just tell you which eye the numbers belong to, not how “good” or “bad” your eyes are.

TL;DR: OD = right eye, OS = left eye, OU = both eyes.

Information gathered from public forums or data available on the internet and portrayed here.