"Todd Pattist" wrote in message
...

It's not speed, it's brightness. If you can squeeze enough
energy into the 1/20000 second, you can do the eye damage
before the glass darkens. Lasers can make high energy
femtosecond pulses. Welders can't.

Todd............

Jes' kidding about the speed - but you knew that. )

But - I didn't know what other quality might be responsible for retinal
damage - color, frequency, brightness or penetration of the shield.

Thanks,
Rich