Reflection off Mirror?

[buildalaser]

Ok so just now I was playing with my new 5mW greenie that I just got today. I decided to shine it around and wave it side to side in the dark to make a cool effect. I shined it too far and it reflected off my mirror into my eye. I'm just wondering if it's less harmful through a mirror and 'cause it's a 5mW will i not even notice it?

 

[daguin]

If it is really 5mW, don't worry about it.

Peace,
dave

 

[Jaseth]

Where did you purchase it? If you got it from somewhere like DX there is a danger that it will be more powerful than 5mW. Some people here have received "5mW" lasers from there which peaked at over 50mW.
If you could post a link or just the name of the company we might be able to tell you if there is a possibility that you need to go to the eye doctor.

Seb

 

[stevo1lasers]

It's a wicked lasers Core

 

[Jaseth]

Ok you should be fine then, Core models are usually at the correct spec and therefore too weak to cause instant damage. If you want to be sure though, check out the Amsler grid: http://www.eyescience.com/images/vision/amsler_grid.gif

 

[Benm]

That grid really is not the best test for laser related injuries - its more geared towards retinal damage over larger areas, not pinpoint damage by a laser hit.

A hit below permantent damage would likely result in seeing a 'spot' for some time after the incident. If such spots last over an hour, there might be reason to be alarmed and seek medical help.

If its really 5 mW, you should be safe no matter what (unless you purposely stared at the beam and tried not to blink). There is a bit of safety margin in these considerations as well - a bit over 5 mW is -potentially- dangerous, but would it most cases not result in permanent eye injury.

 

[buildalaser]

Ok thanks a lot! I appreciate everyone's help.

 

[dr-ebert]

Also it's quite unlikely that the beam was really directly reflected into your eye - that would take a rather remarkable precision in alignment and orientation of mirror, laser and eye. It's likely that the beam passed somewhere close to your eye (a few cm distant) and you got a bit of spill.

Some time ago, when my red had again sucked the battery dry and it was just giving off a very weak beam, much less than the usual red keychain pointer, I did look directly into the beam as a test from a few meters away. It was still amazingly bright, so bright it overloaded the light receptors and looked orange... a real direct hit of 5mW of green would make you feel an atom bomb had exploded in front of you.

 

[Benm]

Also it's quite unlikely that the beam was really directly reflected into your eye - that would take a rather remarkable precision in alignment and orientation of mirror, laser and eye.

Hmm.. i fear murphy's law does its thing there. While it would be pretty difficult to create the circumstance on purpose, somehow people will manage just fine by accident

 

[dr-ebert]

True indeed. Still, as per my last sentence, I feel this would have been an experience that you wouldn't hand off with a simple "... and it reflected into my eye." and no more :beer:

 

[Benm]

Well, a mirror is rare indeed, but i've had it with window panes. Just with low power (50 mW or less) pointers, where you point at something through the window and eventually hit yourself in the face with the reflected beam.

Obviously its no where near as dangerous as a mirror since glass relfects about 4% at a straight angle compared to >90 for a good mirror, but still

 

[bobhaha]

how about you get your self a pair of saftey glasses and then you dont have to worry about wrecking your eyes? just a suggestion

 

[lasersbee]

That sounds about right....bobhaha...

Jerry

 

[Benm]

If you want a to user a laser to point something out, wearing glasses is not a solution

I suppose walking out on the balcony isntead of pointing through the window would be better, but then again, you're not going to when its freezing outside.

 

[Laser_Ben]

Ok so just now I was playing with my new 5mW greenie that I just got today. I decided to shine it around and wave it side to side in the dark to make a cool effect. I shined it too far and it reflected off my mirror into my eye. I'm just wondering if it's less harmful through a mirror and 'cause it's a 5mW will i not even notice it?

If you got a direct hit, you received approximately 80% of the light from the laser. Second surface mirrors have very high losses.

For 5mW, it isn't a major hazard, but this should be a warning to NOT try this again, especially if you have a higher power laser. If you were using a 100mW or above laser, you could well be blind in that eye or have permanent damage. It is very unsafe to use a laser in a room with a unprotected mirror.

 

[Benm]

I suppose thats the reason anything over 5 mW isnt considered a toy

That said, the actual danger seems fairly limited in practice - there are a huge number of more powerful lasers out there, but so far laser-related injuries remain rare.

With hits like these, the laser being handheld is probably something that helps - you just shine it around, and somewhere in the swing you hit the mirror and reflect it into your eye. In such incidents the beam often just 'sweeps over' the eye, leading to exposure time well under what the blink reflex provides.

Getting five mW into the eye long enough to blink is probaby a very unpleasent experience and will have you seeing spots for a while.