Calling BS on this one.

LSRFAQ said:

BoostJan,

I think the man received corneal and tissue abrasions from rubbing his eye. Considering the measured NOHD of a 1.1 watt Wicked Lasers blue pointer is ~600-800 feet, I have nothing more to work with as I do not know the exposure distance, exposure time, speed of the vessel, and true divergence in both axis of the "pointer".


Let me throw in a few more things here, based on hanging out around commercial shipping when I was a kid. Plus something often neglected in the simplified view of laser safety, which is "Optically Aided Viewing".

IF he was wearing eye glasses and thus had an effective 50 mm collection aperture, instead of a 7 mm pupil aperture, what he is saying may become somewhat plausible.

If he had binoculars in front of his eyes, the numbers get "believable".

But we can safely assume he irritated his eye rubbing it. It is a common, and I mean common, reaction to laser flashes. The media might have taken a common American Phrase "Rub Burn" and turned it into a "third degree burn".

Anyone who has played baseball or soccer knows sliding abrasions can hurt like hell.


This is the probably the situation as the Delta Airlines pilot, who claimed he had corneal damage from a non- Q-switched green laser.
If you read his statement, he rubbed his eye profusely after the beam hit him.

Which is more plausible, secondary injury or a thermal burn on a small spot of his face from a diverging blue LD? At close range, I'd admit he could easily have a thermal burn and eye damage, but at more then a few hundred feet, something else happened.

Without a doctor's statement, all I can do is speculate, in the hopes that a few LPFers learn about secondary injury and OAV.

After 20+ years in the business, I'll use one of my titles.. Which means I do have some formal education in this area. From what I am reading, I can speculate that you are hearing about an abrasion.

We don't have enough data to reconstruct anything, which is why I said "probably" in my first post.


Steve Roberts, Certified Laser Safety Officer...

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LSRFAQ said:

I have to disagree here. But only with the semantics..

Some place at home I have the equations stored to calculate the energy delivered from Aided Viewing. It would be significant in this case, If he had the right pair of glasses with a converging lens.

Its not "self inflicted" when an outside, unexpected, event like this causes a nearly involuntary reaction. He did what his brain would have done anyways, which was to try to move the "sharp object" before further damage was done.

From the legal and medical points of view, the laser hit initiated the damage. His response was exactly as expected.


Steve

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H2Oxide said:

That's pretty much what I meant. I should have worded it differently.

Of course he's going to react when a laser hits his eye, and I'm not saying that it's not the culprit's fault. But when I said "self inflicted" I just meant that it wasn't directly inflicted by the laser, and was an indirect result of the laser strike.

The laser is the root of the other problems, but it didn't directly cause them, his hand did. If he had been prepared for it, he might have reacted differently.

Also, I'd love to have a look at those equations if you find them! :beer:

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LSRFAQ said:

Not so HA-HA, Probably not so much BS in this case... The media is wrong, but they have it half-assed correct.

Quote ""burns on the outer coating of the eye and broken blood vessels.""

Its probably a "Secondary Injury", something that you only find mentioned in a few really good laser safety textbooks.

Classic definition of secondary injury: Your climbing a ladder and get flashed by the laser, your startled, and fall off the ladder.

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Benm said:

This might be a media mix up there, but there are fairly standardized limits for first, second and third degree BURNS. This has nothing to do with the chain of causality, but only with how bad the burns actually are and what their permanent effects are.

Obviously getting startled by a laser beam could cause you to fall off a ladder into a pool of lava resulting in 3rd degree burns, but in such a case it would not be fair that the laser caused 3rd degree burns. Shouting in the same circumstance could result in exactly the same thing, but noone would seriously consider that shouting -causes- 3rd degree burns.

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