1watt 445nm question.

[sablehilt]

So I received a 1watt blue laser the other day, I got safety glasses with it but I'm wondering if I can shine it inside without it hitting a mirror like object and look at the dot without glasses. Of course I'm not going to look at the dot from like a foot away but how about 5-20 feet away? Is it safe at that distance or will I cause permanent eye damage?

 

[thatguynate]

It's never a good idea, just in case you do accidentally hit an errant reflective surface, so while I don't think many people around here would recommend it, you would probably be safe for brief glances. I would avoid doing it around any white or similarly bright colored surfaces, as that is still going to be a lot of somewhat-diffused light.

That said, and with the caveat that I am no expert and from time to time a bit foolish, I have done similar things. Perhaps aim with glasses on, and then take a quick look if you're really curious. The truth of the matter is that you never really know, and you only have two eyes so it always always always makes sense to err way on the side of caution, even if that is the less "fun" option.

Its hard to calculate because of how varied what you're hitting can be, and most calculators assume worst case scenarios. Luckily, most of the 445s on the market are multimode and have pretty poor divergence, so the danger drops pretty quickly. You can also reduce the danger by doing this in a brightly lit room, reducing your pupil diameter. Eye damage doesn't always rear its head right away, so just BE CAREFUL.

 

[TheDukeAnumber1]

I would say yes you can look at it, but only for brief instances. If you look for too long you'll notice afterimage, which isn't the end of the world but isn't good for you either.

 

[thatguynate]

That's probably a good rule of thumb. If you see any yellow spots after you close your eye, it was too long or too close. Keep in mind you likely wont FEEL the damage, and you might not notice any problems until a good while after.