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Checking eyes with an LED

Discussion in 'EMS Talk' started by adamjh3, Jun 4, 2010.

  1. adamjh3

    adamjh3 Forum Culinary Powerhouse

    Location:
    San Diego
    Question: Is checking someone's eyes (essentially just PERRL) with an LED - using only the spill, of course - harmful? I've heard arguments for both sides, and I've researched and come up with conflicting information.

    Thanks

    -Adam
  2. EMSLaw

    EMSLaw Legal Beagle

    Location:
    New Jersey
    I'm going to probably regret this answer, but...

    If manufacturers like ADC sell LED penlights, I can't imagine they are harmful to the patient.
  3. Sandog

    Sandog New Member

    Location:
    San Diego,Ca.
    As a former Field applications Engineer I can tell you this. LED's come in a variety of flavors ranging from red, green, blue, yellow to white. Brightness levels range from ultra bright (which may hurt eyes to look at) to not so bright. Controlling the light intensity of an LED is a simple matter of a single series resistor and can be adjusted in such a way as the light intensity is not harmful to the human eye. I am sure there are LED penlights specifically designed for medical use where the luminosity is corrected.

    I would suggest that you use a LED penlight designed for medical use and not one from Home Depot.

    The benefit of LED is long battery life and reliability as compared to an incandescent bulb.
    Last edited by a moderator: Jun 4, 2010
  4. adamjh3

    adamjh3 Forum Culinary Powerhouse

    Location:
    San Diego
    I'm a budding flashaholic, which is why this topic came up.

    One of my friends (whom does not work in the medical field) also brought up the issue of color retention of an incan vs. an LED. I think I'm just sticking with an incan, for now.
  5. Sandog

    Sandog New Member

    Location:
    San Diego,Ca.
    Okay, I have to ask, what is a flashoholic?
  6. W1IM

    W1IM New Member

    Location:
    Berkshire County, MA
    EMS Training:
    EMT-Basic
    Someone with an obsession with flashlights and/or lighting in general. I may have been accused once or twice.


    I carry a surefire e2e incandescent which could burn the eyes right out of your head, but I have used the wide spill to (carefully) check pupils before. I have also used LEDs. In my opinion an LED light with a nice smooth pattern is superior to those 5 cent disposable pupil penlights most ambulances stock. They are quite often too dim and the artifacts in the light can make it very difficult to see any detail in the eye.

    As long as the LED is close to regular white light, the eye should react about the same. The biggest difference between LEDs and incandescents is that incandescents produce a lot of infrared light in addition to visible light and LEDs don't.

    Especially with cooler (more blue) LEDs, colors may not be as easy to see as with incandescents, but there are many LEDs available now that are not as susceptible to this.
  7. mcdonl

    mcdonl New Member

    Location:
    Southern Maine
    I have a surefire on either side of my helmet, on my XD and my AR but I could not imagine pointing one of those at a patients eyes!

    I guess it would work just fine but would be pretty blinding. Hi, my name is mcdonl... I am a flashaholic too :)
    Last edited by a moderator: Jun 9, 2010
  8. Fox800

    Fox800 New Member

    Location:
    Fort Worth, TX
    The best way to be sure is to just carry a legit, actual penlight with the pupil gauge on the side. That way you're not "eyeballing" it (har har) when you guesstimate pupil sizes for your narrative.

    If you're using a Surefire to check pupils you probably deserve a smack on the back of the head.

    This post brought to you my Captain Obvious.
  9. mycrofft

    mycrofft Still crazy but elsewhere

    Location:
    Central California
    Hi, I'm Mycrofft and I'm a Flashoholic too!

    ...and I thought my malady was without a name! I give flashlights for Christmas!

    I was never fast enough to shine the little penlight in their eyes, then whip it up to measure their pupils. Oh, wait, you measure them in ambient light...:blush:

    The LED's on most flashlights are actinic (lots of blue and sometime into long wave UV), and not much red or IR. Shine one into your eye and see what it is like.B)
    Checking for redness of the conjunctiva, the throat, etc. is not well done with them, blood can be missed.

    Now...I was using a nine-unit LED for pt assessment and seeing in the dark, but if I needed good color vision I pulled out my four dollar, two-AA light with the added-on Krypton bulb. I checked pupils with the sidewash of the LED but very quickly, and with adequate lighting around me to see the pupils after my flash had passed.

  10. reaper

    reaper Working Bum

    Location:
    In a Fantasy
    And why would this be?

    If you know how to correctly assess pupils, you could use a spotlight!;)
  11. Fox800

    Fox800 New Member

    Location:
    Fort Worth, TX
    Yes, lets use a 2,000,000 candlepower unit to check pupils. Hope you dont trip or get pushed while you're doing it...ouch for your patient. Lets also use Mac/Miller 4's on babies because we can! If you can make it work it's fine, right?

    No.
  12. reaper

    reaper Working Bum

    Location:
    In a Fantasy
    exactly. The light should never be shined directly into the eye. It should be brought in from the side, until the light starts to hit the pupil.
  13. adamjh3

    adamjh3 Forum Culinary Powerhouse

    Location:
    San Diego

    True, but I've tried it on myself with both a low low incan (mag solitaire) and a low low LED (Quark AA on moonlight mode) and the LED caused some discomfort, even with just the spill of the beam. But that could be a biased study.
  14. Sandog

    Sandog New Member

    Location:
    San Diego,Ca.
    Perhaps this may be true for a penlight purchased at your local hardware outlet, but true white LED's as would be used for medical use produce an even distribution of RGB as can be seen in the graph below, taken from an LED datasheet. Considering that the human eye only has receptors for RGB, other colors are irrelevant.

    [​IMG]
  15. clibb

    clibb New Member

    I bought an LED penlight from Wal-Mart for $3.06 to be exact, that's with the tax included :p .
    I liked it because it was cheaper then a regular pen light. But, this one I'll use for tying flies in the dark and if someone would happen to fall on their head or get a concussion when I'm out camping or fishing. For when I'm on the bus, I'll use the regular penlights they have there.
  16. You use a laryngoscope to tube an infant?
  17. mycrofft

    mycrofft Still crazy but elsewhere

    Location:
    Central California
    Color receptors are nearly irrelevant.

    We don't have receptors for short wave UV and it will actually injure cells, including the cornea and the lens, given enough lumens/minutes.

    The pupillary response can be elicited even in animals with few color receptors because the black and white receptors (the ones we used to use for TV) are all you need. Oh, and intact neural pathways too.

    Nice that they are getting the LED's tuned in better though. Now they need to outlaw them on headlights.
  18. Sandog

    Sandog New Member

    Location:
    San Diego,Ca.
    I am not aware of LED's giving off UV light, care to share this info? Of couse they do make UV lights, but this was done intentionally.

    I agree, those LED headlights are obnoxious and blinding at night.
  19. Fox800

    Fox800 New Member

    Location:
    Fort Worth, TX
    I suppose you could get by without but yes...Miller 0 would fit the bill methinks.
  20. mycrofft

    mycrofft Still crazy but elsewhere

    Location:
    Central California

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