[Dan Evans]

Even ten years later, I still have "blank spots" where I have to shift my head slightly to get something into view.

Were you wearing protective goggles?

[dread78645]

Were you wearing protective goggles?

No. It wasn't required until '92 just as I was laid off.
Anyhow, wearing goggles is stupid for that kind of work. You're centering the beam past two stationary mirrors up to a oscillating mirror.
That would be pretty tough to do if you're wearing goggles and can't see the beam.