405 nm LASER SAFETY

[The_Doctor]

Annoying browser error, dupe post deleted.

[mixedgas]

[QUOTE=The_Doctor;73952]I've had about 92 mW of 405 nm light shining on a white wall in my room for at least three months now, during a long term test. The only change in my vision is that due to hyperopia associated with aging. Granted, I don't stare at the spot at length, but it is easy to see at most times. I use the thing as a night light. The longer this test lasts, the less anxious I am, as no change in either the laser or my vision results. I just take care to avoid a direct hit.


Ah, dude, what are U smokin?

I want real evidence, ie documented stuff.

Steve

[The_Doctor]

Then you'll just have to pay for it like everyone else! We live in a world where the only EVIDENCE that counts costs at least £60 or so, in the form of written evidence from a trained professional who is a member of a recognised body. Sod the fact that these people ONLY get their evidence from studying actual things that other people do because they themselves by definition are NOT either a large, or impartial, sample. If you can't take real first hand evidence when it's handed to you for free, ok, but in that case you'll just have to buy it like everyone else does when they want 'authority' to hand it to them.

Put it another way: if I did what I did as part of a recognised clinical test I'd be paid a damn sight more than than a copy of that evidence would cost you. What exactly is it about freely given info from a single person that is so suspect? If you really want to know, test it yourself. Sounds to me like you might not trust anything less.

[mixedgas]

Put it another way: if I did what I did as part of a recognised clinical test I'd be paid a damn sight more than than a copy of that evidence would cost you. What exactly is it about freely given info from a single person that is so suspect? If you really want to know, test it yourself. Sounds to me like you might not trust anything less.[/QUOTE]

Sounds like I would like: scientific method in a recognized journal, not conjecture because you exposed your (insert body part here) for n mW/cm^2 every day. Just our luck your the one bloke with a different chromosome set or a slightly different protein, as so often happens these days, and thus more resistant from damage.

Anecdotal evidece, unless you have snow white corneas and have never been in the sun since you were born, doesn't cut it!

:-)

Steve

[QUAZAR]

How would the UV radiation from a 405nm laser compare to that of 400W UV cannons (mercury vapour lamp) used in nightclubs? I presume the cannon would be nearer to 390nm, but people are often exposed to these for 8 hours at a time.

[aijii]

good point.. uv cannons and general blacklight tubes etc....

[The_Doctor]

Steve, it's a funny scientific inquiry that rejects one of the first bits of evidence that comes its way. It all starts with anecdotal evidence, how else does anyone get an inkling of what might or might not be going on?

What would you have people do? Get normalised assessments of biological and optical function, then clamp their heads in vices and use some kind of optical speculum to wedge their eyelids open while you timed their exposure to a precisely quantifed source of emission?

Most people wouldn't accept a report of such an experiment if it came to them in triplicate because it's not realistic, never mind the moral grounds for objection.

You might not like what you see in my statement, but it's a fact. If I'd claimed a special case you'd be berating me citing facts of how humans really aren't all that different.

Just accept that if I can spend months in a modest sized room in fairly close proximity to scattered 405 nm light from a near-100 mW source, without any degradation of sight attributable to it, then I think bar staff in a night club can be assumed to be safe. Right now it's not like they can get 405 nm lasers any stronger than mine, is it? For an example of practical, real world exposure, mine is good. As time goes by there will likely be more similar. Real scientific enquiry might not even begin till such accounts indicate a need for it. And as QUAZAR and aijii said, there are plenty of other sources used in such environments more likely to cause similar effects on vision. (mainly cataracts and colour distortion).

You can claim that my lack of accredited scientific establishment counts against me if you like, but my claim that dismissing personal direct evidence is bad science will carry more weight. Sure, you can ask others, get more info, but dismissing anything is just bad science. Scepticism is often a fine word that disguises a simple inverse of credulity.



EDIT: And on a scientific balance of probablility, how often do you find that I talk out of my ass? Not often, I hope.

[mixedgas]

the 365 nm light from the blacklight cannons is even more bioenergetic by a factor of 3 or 4 , and there is a lot more of it per evening. After having 354 nm uv induced conjunctivitious once, from using a poorly shielded eprom programmer when I was in college (had to do 500 eproms a day) NO way I'd blast my audience with that for more then a few minutes at a time. If the wrong type of lamp is used, you get 253.7, much, much more energetic.

conjunctivitious is a sunburned cornea and eye tissue, and it hurts like someone poured alcohol in your eyes for about 20 hours straight.

The only thing remotely making this tolerable is inverse square law.

IN the US, FDA rules exist for mercury vapor UV light exposure, and that club's 400 watts would be considered a very dodgy use.

Somewhere I read about a circus owner installing used, bare, lamps from tanning beds as black light glow lamps on childrens rides , oy vey.....

A few minutes wont hurt, but day after day exposure for the staff and regulars is bad...

When I was in college, I worked with a teen princess who would tan herself light brown week after week after week. With red skin from erythermia, you could tell when it was tanning night, she'd have real pain the next day, as this progressed, she'd have anemia and joint pain. MY bet is she is no longer with us, 10 years later. But she had to have that whole body tan for that short nearly topless, bare midriff sweater and cheerleader skirt, and she was too shallow to know better. She had to be cool. I did my best to warn her, but it went in one ear and out the other. She knew she was in pain, but willing to pay the price for being mega "A" list.

Best way to put it was imagine looking at a evenly deep fried girl, almost beet red once every two weeks.

Remember, those of us who work with technology have the duty to protect those who trust us.

UV exposure is cumulative, our creator gave us just enough resistance for life someplace mellow as far UV goes, human generated UV, or high solar altitude UV just wasn't part of the plan

UV is still limited to far less then the visible limit of 320 uW per cm^2 per 8 hour day in the US. I'll find the limit number.

So that could give you a idea of where to start the math.

Steve

[mixedgas]

[QUOTE=The_Doctor;74031]Steve, it's a funny scientific inquiry that rejects one of the first bits of evidence that comes its way. It all starts with anecdotal evidence, how else does anyone get an inkling of what might or might not be going on?


Do some reading, you'll find that it can take a decade for symptoms to creep in.
When they do, its fast and nasty and spreads to internal organs quickly.

Argument again rejected.

Steve

[QUAZAR]

the 365 nm light from the blacklight cannons is even more bioenergetic by a factor of 3 or 4 , and there is a lot more of it per evening. After having 354 nm uv induced conjunctivitious once, from using a poorly shielded eprom programmer when I was in college (had to do 500 eproms a day) NO way I'd blast my audience with that for more then a few minutes at a time.

IN the US, FDA rules exist for mercury vapor UV light exposure, and that would be considered a very dodgy use.


Steve

Ahh, I was a bit high on my guess for the wavelength. I dont know abous Aus or the rest of Europe, but there are no restrictions for using UV in a night club environment. Many clubs now open all night and having 4 x 400W cannons installed is quite commonplace.

Interestingly though, there are regulations for tanning salons.

Although not arguing your point about UV radiation from 405nm laser emission, it would appear the the UV cannon is inherently more dangerous, but less restricted in its use and application.