If One Pupil Suddenly Looks Bigger Than the Other, Call 911 Immediately

At Big Laps, we cheer on every rider, runner, and weekend player. Active living comes with signs to watch for. Here’s one worth knowing about, and it involves your pupils (the black circle at the center of your eye). If you realize that one is bigger than the other, consulting a doctor is recommended. Why? It can signal a serious issue with your brain.

The Good News First

Not every pupil difference is a problem. According to MedlinePlus, slight disparities are seen in up to 1 in 5 healthy people. And Ubie Health says that this harmless variation is mild, stays the same over time, and is usually under 1 millimeter.

There’s a term for this: physiologic anisocoria. However, a sudden change in the size of a pupil should be seen as a medical emergency, especially alongside other warning signs.

When to Call 911

MedlinePlus says unequal pupils need immediate medical attention when they come with symptoms like a headache or a drooping eyelid. Hashemi Eye Care instructs you to call 911 as soon as possible if unequal pupils are new and associated with any of these:

• A Sudden, Severe Headache: Ubie Health describes it as one of the worst headaches of your life.
• Weakness or Numbness: This occurring on one side of the body is a valid cause for concern.
• Confusion: This and a change in alertness are warning signs to look out for.
• A Recent Head Injury: If one pupil becomes larger after any bump, blow, or jolt to the head, call 911. A difference that shows up weeks or months after a head injury also needs same-day medical attention. Call your doctor or go to the emergency department.
• A Drooping Eyelid: A newly enlarged pupil alongside a drooping lid on the same side needs emergency assessment.

After a Hit to the Head

This matters most if you play contact sports. The CDC lists one pupil being larger than the other as a danger sign after a bump, blow, or jolt to the head. And this warrants going to the emergency department right away.

Why Doctors Take It Seriously

A bulging blood vessel can press on the nerves controlling the pupil. Hashemi Eye Care warns that a big pupil alongside a drooping eyelid can be an indicator of a brain aneurysm. This is a medical emergency, and swift treatment can save a life.

Don’t Know If It’s New?

Look through old photos. This includes your driver’s license, yearbook, family photos, and photos you took years back. 

The American Academy of Ophthalmology notes that some people only notice the difference when they compare old and recent photos. If the difference shows up in all of them, it’s likely longstanding rather than new. This is reassuring; but only an exam can confirm it.

That said, if you find out the change wasn’t sudden but you still feel fine, don’t ignore it. Optometrists.org says it’ll be best for you to schedule an eye exam when you can to rule out anything serious.

FAQs

Can eye drops make one pupil bigger than the other?

Yes. MedlinePlus says that eye drops are a common cause of pupil disparities that are harmless. Asthma inhaler medication can do the same thing if it drifts into the eye.

Is urgent care okay for unequal pupils?

Not always. You’d be better off going to the emergency department, not urgent care, if unequal pupils are associated with double vision, vomiting, or eye pain.