How dangerous is my laser?

[hiphiphooray]

I've been playing around with my new 150mw green laser pointer and found my eyes hurting a little afterward (just feeling slightly heavy and tired). I believe its 150mw, from O-like. I know not to shine it in anyones eyes, but I'm wondering how dangerous it is to look at the beam, dot, and to hold it near me (due to infrared since it probably doesnt have an IR filter).

 

[Zeebit]

All lasers are almost equally dangerous no matter the power. The danger is how you handle the laser.

Try not to look at the dot if it hurts you. Besides, it is dangerous if it reflects back to your eyes.

The beam is perfectly ok to view. As for the IR, the green will get you first before you have to worry about it.

 

[grainde]

All lasers are almost equally dangerous no matter the power.

That's not exactly true... a 1 mW cannot be considered as dangerous as a 2.5 W. There are many factors which will determine how dangerous a laser is eg power, divergence, focal point, wavelength (some wavelengths are even absorbed by the cornea and don't enter the eye). Yes you should be careful how you handle a laser, no matter what the power, but that doesn't mean they are all equally dangerous.

 

[Zeebit]

I missed that part but most "5mW" eBay and other cheapie lasers are pretty much overspec and these pose hazards.

 

[grainde]

I missed that part but most "5mW" eBay and other cheapie lasers are pretty much overspec and these pose hazards.

Thats true, but those are not 5 mW and thats the point. I was objecting to a sweeping statement claiming all lasers were dangerous irrespective of power, which is simply not true! :beer:

 

[Zeebit]

Ok you got it right. Thanks for correcting that.

 

[hiphiphooray]

I understand that I should be careful, and I always try to be. But, I don't want to have to wear safety goggles, as the laser is mainly just to show off to friends. I have a diffraction cap that makes a large array of dots that I project on my ceiling, and after a while I hurts my eyes to look at. Is this normal, or would a lower power laser be different? Also, if the laser did manage to reflect back into my eye, would damage be caused before I could shut my eyelid? I love shining the laser onto random objects to see their illumination, so I would assume there is a chance that it could reflect back into my eyes.

That said, I know I SHOULD wear goggles, but I would rather buy a safer laser than goggles. Since I would need to buy and carry around multiple goggles just to show off the laser, it would kind of defeat my purpose.

 

[Zeebit]

Anything above 5mW has the potential to cause blindness if it hits the eye because the blink reflex is not fast enough to prevent damage. That being said, there are a lot of factors that could determine if the reflection is dangerous or not.

 

[Bionic-Badger]

Usually I just shine the lasers on walls or into the sky if I want to show it off without goggles. The key is to make sure it's not going to reflect back at us.

It's like shooting a gun: they can all kill you, but you just need to be very careful with how you handle them.

So the answer to your question: the laser is dangerous and can permanently blind yourself, so you need to be careful.

 

[brendon7358]

I just saw this the other day, I don't remember where but staring into the sun is equivelent to shining a 2mW laser into your eye, I believe on average 10-15% of laser light is reflected off objects (walls etc). So staring at the dot for a minute is equivalent to staring at the sun for 11 minutes.

p.s. I could be completely wrong but I sear I read all this somewhere

p.s.s. Although it may be true because if you think about it if your outside on a sunny day even if your not staring at the sun at the end of the day your eyes get that tired feeling.

 

[Eudaimonium]

I'm not really sure what do you mean by hurting eyes after viewing a lot of lasers...

I've never had any such feeling after looking at bright light sources.

In any event, just always double check your target, make sure you won't have any reflections and you're good. Goggles should be worn when staring into bright dot is unavoidable - burning stuff, engraving, aligning dichros or mirrors or whatever.

Diffraction grating is dangerous as well, majority of the dots scattered are powerful enough to cause some damage, so you might wanna take extra care around that.

 

[TheDukeAnumber1]

@ hiphiphooray

The things that you need to look out for are direct beam to eye exposure and reflections exposure. These things have the potential to cause immeduate damage. Otherwise looking at the dot of a green 150mW to closly we all will tell you is bad for your eyes, but how bad is hard to say and really depends on a lot of variables.

Overexposure will put unecessary stress on your eyes, whether this is worth it is up to you.