The OD medical abbreviation most often means right eye, from the Latin oculus dexter, and it appears on eye drop prescriptions, eye exam notes and glasses or contact lens prescriptions. In an emergency or toxicology note, OD usually means overdose, and on prescriptions from Britain and several other places it has stood for once daily.
Those overlapping meanings explain why the national medication safety group ISMP warns against OD, together with OS for left eye and OU for both eyes. A once daily oral medicine read as right eye can end up in someone's eye. Below, you will find each use in a sample line, how to sort them out and the safer wording now printed on most labels.
At a glance
Stands for
Right eye (eye care)Latin origin
Oculus dexter, right eyeOther meanings
Overdose (emergency care); once daily (some countries); Doctor of Optometry (credential)Written as
OD, o.d.Safety status
On the ISMP list of error-prone abbreviationsSafer to write
right eye; daily or once dailyDo not confuse with
OS (left eye), OU (both eyes), AD (right ear)
What the OD medical abbreviation means in eye care
In ophthalmology and optometry, OD is the standard label for the right eye. An eye exam note lists findings for OD and OS side by side: vision, eye pressure, the look of the retina. A glasses prescription lists the lens power for OD on one line and OS on the next.
On medication orders, OD tells where an eye drop or ointment goes. "1 gtt OD" directs a single drop into the right eye only. As a pharmacy abbreviation it is fading: most labels now replace it with the words right eye, which removes guesswork for patients and caregivers.
Sample lines with OD, decoded
| As written | Plain meaning |
|---|---|
| VA OD 20/40, OS 20/20 | Vision in the right eye 20/40, left eye 20/20 |
| IOP OD 24, OS 18 | Eye pressure 24 in the right eye, 18 in the left |
| Moxifloxacin 1 gtt OD TID x 7 days | One antibiotic drop in the right eye three times daily for seven days |
| OD: -2.25 sphere | Lens power for the right eye on a glasses prescription |
The pressure line uses IOP, intraocular pressure. These lines show the format only.
OD as overdose
In emergency departments, poison control notes and toxicology consults, OD means overdose: too much of a medicine or other substance taken at once, whether by accident or on purpose. You might read "OD on acetaminophen, presented 4 hours after ingestion" or "suspected opioid OD, naloxone given."
ED triage note: "Brought in after accidental OD of child's cough syrup, alert, vitals stable." No eye is involved; the setting and the drug name make the overdose meaning clear.
Some overdoses are intentional, and these notes are written in neutral clinical language. In the US, anyone in crisis or worried about someone can call or text the 988 Suicide and Crisis Lifeline at 988.
OD as once daily, and why that is dangerous
Prescribers trained in the UK, India and elsewhere have long used OD to mean once daily. In a US pharmacy or hospital, a reader trained to see OD as right eye can misread the order. Medication safety reports describe cases where an oral liquid ordered "OD" was put into a patient's right eye.
For that reason, the safer practice everywhere is to write daily or once daily. The older US shorthand for once daily, QD, is itself banned by The Joint Commission, so neither abbreviation is a good choice.
OD, OS, OU and the ear abbreviations
| Abbreviation | Meaning | Safer wording |
|---|---|---|
| OD | Right eye | right eye |
| OS | Left eye | left eye |
| OU | Both eyes | both eyes |
| AD | Right ear | right ear |
| AS | Left ear | left ear |
| AU | Both ears | both ears |
The pairs differ by a single letter, so an ear drop can be put in an eye or the wrong side can be treated. Writing the words solves both problems. The prescription abbreviations hub collects these and the other error-prone terms.
OD after a clinician's name
When OD follows a clinician's name on a badge, report or office door, it means Doctor of Optometry, an eye care professional who examines eyes, prescribes glasses and contact lenses and treats many eye conditions. It is a credential, not an instruction, and you will see it on exam reports and lens prescriptions.
This page explains general meanings. If a label or note leaves you unsure which eye, or whether a medicine goes in the eye at all, check with your pharmacist or eye care clinician before using it.
Frequently asked questions
What does OD mean on an eye prescription?
OD means right eye, from the Latin oculus dexter. Its partners are OS for the left eye and OU for both.
Does OD mean once daily?
In some countries it has been used that way, but it is easily confused with right eye. In the US, write daily or once daily instead.
What does OD mean in an emergency note?
In emergency and toxicology notes, OD usually means overdose, taking too much of a medicine or substance.
Which abbreviation means right eye?
The traditional abbreviation is OD. Because it is on the ISMP error-prone list, many labels now print right eye in full.
What does OD mean after a doctor's name?
It means Doctor of Optometry, the degree held by optometrists.