Assessment of light reaction of pupil

Here.I.Stand, BSN, RN · Mar 12, 2014

Non-reactive is exactly that--you shine the light in someone's eyes and their pupil does nothing.

Say their pupil, while sitting in their room w/ its ambient lighting, is 4 mm across. Shine a pen light in his eyes, and the pupil suddenly becomes 2 mm across. If you leave the beam there, it will stay 2 mm--the muscles in the iris "want" to keep it at 2 mm to limit the light hitting the retina. If you take the light away, it will go back to 4 mm. All this means the pupil is reactive.

Esme12, ASN, BSN, RN · Mar 12, 2014

shine light in the eyes pupil constrict, continue shine light is still shining light in the eyes, right? Pupil will be non-reactive?

A non reactive pupil will not change with any light source...ever. It does not dilate in darkness nor will it constrict in light. It stays the same.

Once the pupil changes at all to a light source it is reactive.

NutmeggeRN, BSN · Mar 12, 2014

and the first time you see an opiate overdose, you WILL understand what Constricted Pupils realy means!

Here.I.Stand, BSN, RN · Mar 12, 2014

Can you find a willing volunteer--a family member or friend--who you know to be neurologically intact? Then check their pupils? Seeing for yourself what is normal might be more helpful than a description. :)

tkyeung · Mar 14, 2014

for a normal person, the pupil constricts when light is shone on it. For neurologically impaired persons, is it possible that the pupil dilates when it is shone by light?

nurseprnRN, BSN, RN · Mar 14, 2014

for a normal person, the pupil constricts when light is shone on it. For neurologically impaired persons, is it possible that the pupil dilates when it is shone by light?

All sorts of weird things can happen in neuro. The answer to your question is, "yes," but it is abnormal and uncommon. Google is your friend. "Pupil dilate with light" yields this, among others:

Neuroexam.com - Pupillary Responses (CN II, III)

nursefrances, BSN, RN · Mar 15, 2014

I just saw this thread and I love everything eyes.

In regards to reactive/non-reactive: as others have said-don't over think it. The initial response of a light stimulus is what you are looking for. When you shine a light on a pupil is it constricting? Yes...then the pupil is reactive. If you shine the light on the eye and it does not constrict (or enlarges/dilates) it is non-reactive. If you shine the light and it seems to dilate as a first response this is a positive (+) APD which the link in the post above mine explains. Great link by the way. :up: This link also discusses the consensual response of the two eyes(pupils): when shining a light on one eye, the other eye (pupil) will also constrict if it is receiving the full stimulus/light source.

The way it was explained to me (in my old "eye" days) you are looking at the way the eye (and the brain) perceive the stimulus. The light is shined on one eye, which then goes to the retina---->optic nerve------->brain. The brain thinks "hey, that's kind of bright." and sends a message to the iris to constrict making the pupil smaller, it's like your closing the shades a little bit to let less light in on a bright sunny day.

There could be a problem at any of these points (pupil, retina, optic nerve or brain) so it may not always be neurologic in the sense of just brain. There could be eye pathology that affects the pupil's response to the light stimuli. Certain trauma to the eye, like being hit in the eye can cause permanent dilation of the pupil. Certain eye medications as well as some p.o. meds can also cause pupil dilation. If you encounter this problem this is when you use the other eye (the consensual pupil dilation I mentioned and the link mentioned above)

One more thing, to answer your original question: if you keep shining the same light on the pupil for some time, it will not continue to constrict. It will eventually relax some. I checked with some eye techs before posting this to make sure (since I am a little rusty).

tkyeung · Mar 15, 2014

thanks for the information sharing. One more question: Upon the shining of light, if the pupil constricts, then I should chart reactive on the assessment form. How about like said above, sometimes pupil will enlarge when light is shone for some neurologically impaired persons, if this is so, pupil dilates when the light is flashed to the pupil, this is also classified as reactive because a "reaction" takes place?

CodeteamB · Mar 15, 2014

thanks for the information sharing. One more question: Upon the shining of light if the pupil constricts, then I should chart reactive on the assessment form. How about like said above, sometimes pupil will enlarge when light is shone for some neurologically impaired persons, if this is so, pupil dilates when the light is flashed to the pupil, this is also classified as reactive because a "reaction" takes place?[/quote']
That is called a paradoxical reaction, should be charted as such. Charting "reactive" is not descriptive of this abnormal reaction and would be misleading.

tkyeung · Mar 16, 2014

Yes. If a pupil ever changes size it is "reactive". It is only nonreactive or "fixed" if it stays the same size no matter what amount of light it is exposed to.

According to the above comment, then if pupil enlarges upon the shining the light to it, then it should be regarded as "reactive" ?

CodeteamB · Mar 16, 2014

According to the above comment then if pupil enlarges upon the shining the light to it, then it should be regarded as "reactive" ?[/quote']
If you are charting in a system where you are allowed only 2 options, "reactive" and "fixed" then I guess hypothetically you would have to chart the former and refer readers to a note explaining that it was an abnormal reaction.
Do you see the problem with charting simply "reactive" for a paradoxical reaction?

tkyeung · Mar 16, 2014

In my hospital, the assessment only allows me to chart "reactive" (+ sign) or "non-reactive". (- sign) or eyelid swollen. I assume that it wants me to chart "reactive" as long as there is reaction from pupil from the shining of light (regardless of constrict or enlarge). Am I right?