Eye damage from class IIIa laser and reflection from a Plasma TV?

[nyght]

Hey guys,
I figured this was the best place to go to seek an answer to my question. I was in a meeting today and the presenter was using a class IIIa (<5mW) red laser pointer during the presentation. The wavelength of the laser is spec'd to 630-680 nm. During a few parts of the presentation I would look at the plasma TV screen (to where the laser was pointed) and would see a reflection, presumably a reflection from the source of the laser. I suppose I could describe it in the image below:

The duration of the reflection couldn't have been more than about 1 second. I don't have any noticeable symptoms of eye damage but was considering going to the eye doctor tomorrow just to check things out. Do you guys think there's a chance for eye injury in this case?

Thanks,
Jonathan

 

[ZRTMWA]

It's highly, highly unlikely. You should definitely be fine. Eye doc is always an option though if you're really concerned.

 

[Hemlock_Mike]

Doubtful.

HMike

 

[KiLLrB]

There are a few places that sell <5mW lasers that are actually higher output than they state either on the label or the site selling them. It is very unlikely that one of these is what he was using buuuuut.... If you are still seeing spots or anything abnormal I suggest you see an opthamologist to be sure

 

[photonaholic]

I doubt it too, presenters have used those red pens for years, if it was going to be a problem, it would have reared its head a long time ago.

 

[Benm]

As mentioned before: if the laser is truly 3a compliant, its output power should not exceed 5 mW which is considered safe for anyone with a properly working blink reflex.

A reflection often has way less power that the beam causing it (unless its in a mirror), so there should be no real hazard here, and no reason to seek medical attention unless experiencing symptoms.

 

[floridaguy5583]

There's nothing better than seeing a doctor and him telling you there's nothing wrong with you, but i do agree, if in fact its <5mw, then you should be completely fine, but i have heard of lasers, that sell at 5mw or 10mw that output up to 40mW or 50mw, but i doubt that was the one being used.

 

[Bluefan]

ordinary bullet style pointers are about 2mW with fresh batteries, I don't think much red pens will differ much or be overspec'd. You caught a reflection from a glass surface, not a direct reflection. That means you only caught a small part of the power, so I wouldn't worry about it.

 

[Elektrotechniker]

No chance for eye damage. I had direct hits from <5 mw red lasers and didn't get any damage. At that low power, most wavelengths are almost impossible to cause any injuries. Correct me guys if I am wrong but that's what heard here on the forum and from my experience.

 

[Flaminpyro]

If you are not sufering some kind of after effect you should be fine, can you still read small print and not painfull to do so ? if you think you are having a problem go see a doc !

Peace All...

 

[Razako]

Is this a troll topic or something. I mean unless you're seeing spots in your vision or something after the presentation there's nothing to worry about. Furthermore at max you would get like 1/2 mw reflections off the tv from a pointer at that power.

 

[aryntha]

Possibly. The guy could also be worried; I think we've all had moments with our IIIb's where we at least for a moment think, "uh oh, did I just do that..." - So, let's just allay the worry outright:

Not only does glass reflect about 4% at normal angle/specularity, but also most plasma screens are AR coated.

So lets say the IIIa was 10mw over-rated (super cautious, highly unlikely), and by some freak occurance the AR coating wasn't there (also unlikely) and the angle of incidence was just right to reflect back 10%.

1mW into your eye. Probably somewhat defocused. Unless the moon and stars have aligned against you, you still go home happy.

 

[LSRFAQ]

If this is truely a 5-10 mW demonstration device, per the rules.....
You might pick up some eye strain from your aversion reactions. Odds of damage are very low, less then 1 in 100,000 for that power level. Now if the laser were class IIIB, and greater then 5 mW, then things change.

Perhaps your near a LPF member with a power meter?

Steve

 

[Benm]

Also, bear in mind that the accepted safety levels are about permanent injuries.

If you wake someone by shining a 1 mW red laser in their eyes, i'm sure that would be a very painful experience, but no -permanent- damage would be done. This does, however, not mean the victim would not be seeing spots for the rest of the day.

The visual system has a number of 'gain controls' that allow us to see under widely variable conditions - from a moonlit night to daytime in the desert. Exposure to bright light in small spots can seriously interfere with the natural functions of these mechanisms, even when no permanent injury is done.

If you were to experience lasting symptoms after a day or so, that could be cause for some alarm. In the short run (an hour or so) i suppose its best to just let things take their time to settle... there is no method of treating a serious laser injury in that timeframe even if you had one.

 

[LSRFAQ]

Having a ER experience recently for a NONLASER NONOPTICAL eye incident, I learned a few things... I took the time to ask some questions after they got done admonishing me for my own whoopsis.. I had plenty of time as they flushed my eye with saline. No permanent damage, just a scratched/irritated sclara, ie the white part of the eye, at 2 Am in the morning. :tsk::tsk::tsk:

They may/will give steroids, certain vitamins , some other things for a immediate retinal injury, and possibly something to reduce eye strain. They will also do a immediate retinal exam, but it may not be the complex automated one that is likely to spot a minor burn. Time is a factor, the sooner they can get the tissue swelling and bleeding down, the better.

I'm not a MD, I cant tell you when to go or not to go, but the idea is to go get help.

And you may, after a minor hit, by rubbing your eye or straining it, induce eye strain, muscle strain, scratch some tissue, etc

There are probably levels of damage, ie stress, damage from rubbing, bleaching, minor hit, major permanent damage, and if you get near the optic nerve, permanent blindness in that eye...

Good laser safety practices are comparable to gun safety, you have to be mentally prepared ,know the procedures, discuss the procedures, take refresher courses, and DO the procedures.


Steve