Wow. Look what this thread has become. This topic has been discussed several times on LPF, and I think it will always continue to reoccur. Anyway, our eyes absorb ir although we can't see it, and if it's collimated enough could be very harmful because your eye doesn't have any reflex defense aka blink, squint, or even look away. Have you ever saw yourself on an ir camera where it looks like a light is blasting in your face although all your eyes can see is the faint red of the leds? It is dangerous because we have natural reflexes to defend our eyes from light we can see, and we relax, or even open up to more danger when we can't see it. The concept of something harmful that's invisible is frightening and makes people overly concerned about it. To destroy a laser because of this is simply nonsense, erratic, and ignorant.
Uv on the opposite side of the spectrum is still dangerous, still invisible, but our eyes reflect most of it thus significantly reducing the danger vs. ir.
To stay safe from ir, just use common sense and try to keep yours and others eyes away from the beam and watch out/avoid reflective surfaces. Mainly, don’t be messing with ir diodes by them selves without eye protection because your eye will invite the invisible light in to be absorbed by your retina.
