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Laser effects on skin

FarewellToKings

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Let me start by saying that I have always been a "take one for the sake of curiosity" guy. So I was playing with my 130mw WL green and a magnifying glass the other night, and decided to expose the skin on the side of my hand to the focal point for different amounts of time.

Now, a week later, some pretty interesting effects have become apparent. All of the spots were unnoticeable for a day or two, turned red, and now appear to be scabs. But upon closer inspection, they are not scabs. The skin appears to actually be stained brown. The dark color has not faded... its pretty fascinating. The 4 spots are all very small, in case you are wondering.

An interesting side note is that I did an exposure with no optics, and that burn formed a very obvious and raised scab.. not intense enough to cause the brown skin?

Has anyone else been burned before? Did you notice anything similar?

UPDATE

All of the little brown marks eventually faded or flaked away within 2-3 weeks.

I recently received my Spartan 400mw blue. It has a fat beam that gets painful very quickly, so I held it on the side of my hand for as long as what might happen if you accidentally put your hand there... Since the pain seems to be delayed, it was long enough to cause damage. There were no marks for about 12 hours, but then a blister in the shape of the beam (an elongated oval) developed. Its been a week now, and a scab has formed, again directly mimicking the shape of the beam profile.
 
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DJNY

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I noticed the same during burning myself.
Hope your dad gets some nice infos for us!
 

FarewellToKings

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I noticed the same during burning myself.
Hope your dad gets some nice infos for us!
Yes! Duplicated results, haha. How long did the discoloration stick around? And I may have to stuck it up and make a larger spot for a biposy.
 

IsaacT

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Interesting thread....


Srry, just needed to type something so I can see if there are updates to it when I log-in.....hope your hands okay!
 

Benm

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Hmm.. i've been stung by a green while fiddling the adjustment in a projector, but retracted my hand as soon as i felt it. There was nothing to see on the spot, not right after expsure, nor in the long term.

Still, i think you should prevent these things (and not do them on purpose!) - its perhaps something like sunburn, or serious burn if focussed to a small spot. Can't be healthy!
 

IsaacT

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lol.....I would actually be inclined to believe that tho...it only makes sense that it could cause cancer
 

Toke

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I guess that most lasers would damage the skin though heat.

The nasty thing is that on Wiki's page on laser safety there is a mention of blues and photochemical reactions in the retina.

That means that the blue photons are strong/energetic enough to disturb molecular bonds, as in ionizing radiation. That means it can disturb a DNA molecule in just the way that turn the cell cancerous.
Not likely, but that is what cancer risk is all about.
 

Benm

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Update

All of the little brown marks eventually faded or flaked away within 2-3 weeks.

I recently received my Spartan 400mw blue. It has a fat beam that gets painful very quickly, so of course I held it on the side of my hand for as long as I could stand. There were no marks for about 12 hours, but then a blister in the shape of the beam (an elongated oval) developed. Its been a week now, and a scab has formed, again directly mimicking the shape of the beam profile.
Darn.. you're one mad scientist to keep trying. Perhaps you can get one of the > 1 watt 445 lasers to burn a hole straight through your hand, and then see if that heals up eventually as well :D

445 nm is on the range that could potentially break/alter certain chemical bonds, but since we evolved in an environment with plenty of blue light i doubt there is much of a hazard for small exposures. Its the same thing with sunlight though... a little bit isn't dangerous, but if you bake on a beach till lobster-red on a daily basis it's hazardous.

Als for the blue light story - i don't buy much of that. There are some short term photochemical effects in the eye, but those are to be expected. When working with green or blue bright lasers you will experience odd color vision for a short while afterwards (things look pinkish)... same deal with the old green-on-black computer screens.
 

RA_pierce

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As far as I know, 445nm is not a short enough wavelength to be carcinogenic.
That is not to say that it is impossible for it to cause melanoma.
IIRC, the wavelength must be <390nm for it to be considered potentially carcinogenic. You will have a hard time giving anybody cancer even with a 405nm laser.

Exposing your skin to intense laser light is not a good idea regardless of the wavelength.
The result is obviously a thermal burn and pain. It's a no-brainer.
 

Tech_Junkie

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I noticed the same during burning myself.
Hope your dad gets some nice infos for us!
I have some of these on my feet, as do a lot of other people. I did hours of web investigations, and no one had an answer. I then found an article that this old lady wrote, and it answered all the questions. You did damage to your micro capillaries in your hand. When ruptured a minute pool of blood forms, causing the spots. After time the they can be pushed out by the body. If they are deep, like most people who have them on their feet and legs, only walking can rid them from the body.

 

Toke

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Well, I just read photochemical effect and read that as equal to killing or altering cells through disturbing molecular bonds.

There is some difference in photon energy from 390nm to 405nm but the description of delay of effect sound more like sunburn than burn to me.
 

FrothyChimp

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Output from a 532nm is absorbed all the way to the subcutis layer. This layer houses larger blood vessels and nerves with smaller vessels in the dermis above. Blood absorbs 532nm readily with a peak absorption in the 600nm range. Thus the blood vessels are being burned or heated to levels to damage the vessels and the blood cells as well as other structures (nerves, collagen, etc.) well below the surface of the skin. The only wavelengths that actually do not penetrate readily is far infrared (CO2). Such lasers start burning at the surface and work their way down whereas 532nm will immediately affect several layers at once but the power density at any given point is less than the rated output because the beam is being absorbed across several layers (plus there is some diffuse reflection and fluorescence). It's not likely there is any permanent damage as the body will repair the area as in any injury except, perhaps, nerve damage. Damage to skin with visible and IR lasers is thermal in nature. Cancer is not a likely outcome from exposure due absorption outside the nucleus. High energy photons in the low UV range do have enough energy to reach the genetic material within the nucleus if the cell survives the thermal effects.
 

Don't Laze Me Bro

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Output from a 532nm is absorbed all the way to the subcutis layer. This layer houses larger blood vessels and nerves with smaller vessels in the dermis above. Blood absorbs 532nm readily with a peak absorption in the 600nm range. Thus the blood vessels are being burned or heated to levels to damage the vessels and the blood cells as well as other structures (nerves, collagen, etc.) well below the surface of the skin. The only wavelengths that actually do not penetrate readily is far infrared (CO2). Such lasers start burning at the surface and work their way down whereas 532nm will immediately affect several layers at once but the power density at any given point is less than the rated output because the beam is being absorbed across several layers (plus there is some diffuse reflection and fluorescence). It's not likely there is any permanent damage as the body will repair the area as in any injury except, perhaps, nerve damage. Damage to skin with visible and IR lasers is thermal in nature. Cancer is not a likely outcome from exposure due absorption outside the nucleus. High energy photons in the low UV range do have enough energy to reach the genetic material within the nucleus if the cell survives the thermal effects.
Hey frothy! Long time no see man!!! Hows it going?
 




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