- Jun 22, 2011
Less then 20-30 mW of 488 nm light in my case. Stupid College Senior Coworker flopped the lockuput tag off the safety key and turned on the show control computer, while I was forward of a laser show beam table. He could clearly see I was forward of the safety line. The 25 watt capable SP 171 was idling and cavity detuned to align the table at low power. All the shutter arms popped up as the computer reset the table during boot. Thus I got a painful 100-200 milliSecond exposure. (There is not always pain as a symptom!) That was 1989 or so.
I find it strange you got visible permanent damage from 30mW. The MPE/safety calculations all allow for a huge safety margin (if I remember well the margin is 10x the power needed to cause damage) and according to them 5mW is safe as long as you don't get exposed for over 250ms. Maybe you got hit by a higher power or got extremely unlucky and it focused very well on a tiny spot...
If lasers that "weak" could cause long term, perceptible damage we would have the media swarmed with actual laser damage cases, because 100mW lasers are very widely available to children and careless users. This is the kind of thing the media loves and they would be all over it if it was common. Even here on this forum it's very rare to see an actual report of permanent laser damage.
I had a laser surgery to avoid retina dettachment and they used a ~200mW 532nm laser focused to a tiny dot. According to my doctor that is about the minimum power to actually cause a decent retina burn. Even then I only had headache for about 2 days and none of the other effects you mentioned (though the tiny spots were made in the peripheral area, which might make the compensation hard to notice). I also asked her to see if I had any (other) laser damage and she said I don't.
Note that this isn't meant to question your story or advertise against laser safety - it's always better to be safe than sorry!