Safety precautions for a relatively weak 445?

[Alessandros]

Hey everyone,
I posted this same thread in the Safety & Legal Issues, but I suspect it was too wordy, since it now has ~80 and no replies after a few days.

So, I'm planning on potentially making a 250 mW 445nm.
I have a family history of macular degeneration, so I'm trying to be extra cautious around 400-500 nm light.
My question is, without goggles (which I do have), how far away must I point the laser away to be able to appreciate the beam and point without damaging my eyesight?

Thank you!
Alessandro

 

[ElectroMagneticFreak]

I agree with your propensity towards caution since there is some evidence of even low levels of this wavelength causing permanent eye changes in rats after short exposures.

As for the traditional dangers from any laser wavelength looking at the beam without goggles is not dangerous, and you won't be able to see the beam anyways with goggles. With my ~1W 445nm I point it at tree tops a few hundred feet away and don't look at the dot for longer than a few seconds even at that distance although this is probably being very overly cautious. I usually point my lasers much farther away when looking at the dot than others on here but I am a bit of a hypochondriac admittedly.

You problably could point your 250mW much closer than I mentioned above, but like you said with the 445nm wavelength it's not just whether it is too bright to look at there is the cumulative effect of the blue light hazard.

My Grandmother had macular degeneration so I still enjoy my 445nm laser but just limit it to short exposures. I mostly just enjoy the beam when it is pointing skyward or pointing at the far off trees. When I'm not able to use the laser I get my fix by reading about them on LPF.

Here's a link to a thread about blue light hazard and links to two research studies that are a good read that mention the rat study with the blue wavelengths.

http://laserpointerforums.com/f53/blue-light-hazard-beam-viewing-do-you-limit-your-exposure-71374.html

 

[Alessandros]

Thanks a lot, this is some great info!
Great to see another Canadian on here. Can we be neighbours? xD

Alessandro

 

[Ash]

Rule of thumb- if a laser's dot is uncomfortably bright to look at, it has the potential for causing permanent damage.
I find looking at the dot of a >200mW 445nm on a white wall from 20 feet away a bit uncomfortable, and limit my exposure to a second or less without safety glasses. I don't even really use my high powered blues without safety glasses unless I'm outside.
Be warned not to point the laser at reflective material (street sign, license plate, etc.) outside.
Good luck on your build.

 

[Alessandros]

That's a good rule of thumb, thank you!
I'll need that luck, I'm currently working on a LPC-815 build, and I'm waiting for the driver in the mail, so I can find out if I killed my diode or not :crackup:

Alessandro

 

[ElectroMagneticFreak]

Thanks a lot, this is some great info!
Great to see another Canadian on here. Can we be neighbours? xD

Alessandro

Yes! :wave: