I believe my machinist friends call this the "safety squint". :P Their attitude appears to be that a little bit of flash from occasional welding isn't going to hurt you; it's the professional welders who're at it all day who need to take the most care.

I close my eyes. And I have a pretty fast set of glasses even so it's not enough to be able to avoid a blind spot after an hour or more of work. Better safe than sorry. The auto darkening glasses make it much easier to start a weld though, you know exactly where you are relative to the workpiece, which especially with stick welding is the difference between a lot of cursing + frustration and some reasonably good work.