Pupil size (eyes) and epilepsy

Having a seizure temporarily changes pupil size for some persons.  Is it more common for a seizure to dilate the pupil or shrink the pupil?  Why?  Do many persons experience no change in eye pupil size during a seizure?  Insights?  Experiences?


Re: Pupil size (eyes) and epilepsy



Sometimes, when I am in the ER, the doctors notice that the pupil in my left eye remains large. There are days when I have seen this as well.

My son, who is also epileptic, also has days when his pupils are enlarged when they shouldn't be.

Re: Pupil size (eyes) and epilepsy

My fiance says that when I'm having a seizure my pupils dilate. I usually have simple partials, and usually the ones that have severe emotional effects- basically I'm having a panic attack that happens to be caused by a seizure- seem to be the most obvious cause of pupil dilation. I don't know why this is, but I'm more focused on other things (like trying to figure out where I am or what's going on). It would be interesting to know the scientific reasoning behind it.

Re: Pupil size (eyes) and epilepsy

Hi Drowsy...

My best guess would be that during a seizure, and subsequent panic attack that follows, the Sympathetic Nervous System (SNS) is activated. The SNS is the body's fight-or-flight system and prepares you if you need to flee, fight, run, etc. During the activation of the SNS (for people with no sz), physiological responses such as heart rate increases, there is increase in sweating, trembling, dry mouth etc--think how you would feel if you suddenly had to give a speech in front of 1000 people, or were suddenly told you won the lottery. Pupillary dilation is another sign of SNS activation.

My BEST educated guess is during a sz, the brain goes into overdrive, and the neurons are firing randomly and also over-firing uncontrollably, at a very fast pace. It's like a storm in a teacup. 

Extrapolating from this, I would guess that activates the SNS in some way.

In cases where panic attacks happen because of the sz, then it is definitely the SNS that is the culprit, because a panic attack is basically a heightened fight-or-flight response, in absence of a ''''''real danger'''''' (not the ''''''______''''''' I put around it because the person feeling it would definitely feel like there's real danger) and the SNS goes into overdrive then.

Hope that helps!

Re: Pupil size (eyes) and epilepsy

Yes. From my first seizure as a child, my mom noticed that my pupils were so dialated she couldn't see my iris color anymore. I'd say, "I can't see. I can't see." It still happens to me still that, just before I black out, my vision closes in on me. Even if people aren't that close to me to see my eyes at that moment, I'm sure that's what's happening. Good luck to you.

Re: Pupil size (eyes) and epilepsy

Hi pgd,

Bilateral mydriasis (large pupils) is more common with my seizures, while unilateral mydriasis (or anisocoria) is now more common with my migraines. Constricted pupils (miosis) sometimes resulted from medications, and/or changes, complications.

Google "pupil size conditioning" to find all the bizarre effects this frequent aspect of minor simple partial seizures has on social interactions and body language.


Re: Pupil size (eyes) and epilepsy

Hey there,

For me, my pupils become massive during, and sometimes a little before/after a seizure.  Now, this doesn't happen when I have Absence seizures, but it does during Partial/Complex ones.  Of course during those seizures I do bizarre things, so it's common for people to think i'm on drugs, even though i'm not on anything (other than medications, of course).

 Now, why that is, I have no idea.  Maybe it's where in the brain the seizures occur, that's my best guess.  I've never had a seizure shrink them though...

And to answer another question, yes, there are people who's eyes are perfect fine during seizures, my friend in particular who has Grand Mal seizures never has eye changes during them.


But yes, from my experience, it's very problematic having pupil changes during a seizure.  I get alot of negative stigma from staring eyes whenever I have one.

Re: Pupil size (eyes) and epilepsy

My pupils dialate when I have a sz. During and after the last complex parital that I had, my husband noticed that my pupils were REALLY LARGE. My nuero asked my husband at my last appointment if my pupils dialated during one of my sz's so that must have something to do with them...This epilepsy this is so strange...I have done so much research and I still can't figure it out and especially why I was diagnosed at 28 years old? One thing though that I always thought was odd about me is that one of my pupils is usually larger than my other one. I was told that sometimes that has something to do with head trauma. I wonder if my mom dropped me on my head as a baby and just never told anyone! Lol! Maybe that could explain some things? :)

Re: Pupil size (eyes) and epilepsy

My pupils would "dance" before sz. They would start to constrict and dilate rapidly. This was pointed out to me on a few occasions and usually it was when I was feeling very goofy and loopy before hand. I have also had the extreme dilation, but often than not...the dancing is what makes me think something is "going on".

Re: Pupil size (eyes) and epilepsy

Neurological problems in children often cause eye problems if the
nerves that lead to the eyes or the part of the brain that controls eye
movements are damaged or diseased. A vast number of problems can cause
ocular symptoms, which can cause changes in the function, appearance or
movement of the eye.realtor in columbia mo

Re: Pupil size (eyes) and epilepsy

finally found somoen whose do.  Mine do as well they dialte wide open.

One opens faster than the o ther.  then one eye looks kind of bugged out oafterards

scarse me silly.


Re: Pupil size (eyes) and epilepsy

Having been in status several times in my life I have had to keep my eyes closed because of the sensitivity of light.  They all came back to normal.
The pupil dilation does come back to normal.  It effected both eyes then.

Sometimes medication can effect pupil dilation too.  Tegretol did that to me on high dosages and I had a lot of nystagmus and my pupil sizes were irregular because of it.  I think other meds.

Sz are short!

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