Bzzz,
There are several shades of green, including "dark" green as well as "shade 5" which are easily and comfortably worn over (my) corrective lense safety glasses. They do help seeing through the sparks, although the darker shades often are too dark to see through without spark or flame, the handy flip-up feature makes a reasonable work-around.
They seem to be cooler than goggles, and I use them for my torch work in shade5. The salesman says they come in all kinds of shades, but I've only use clear, 5, and dark green.
As you're shopping try to decide which suspension style you prefer.Fibre-Metal makes at least three types of suspension frames for the shields. The difference is in the size of the hinge-up gadget that holds the actual replaceable safety shield lense- I think it's called the crown, I forget. I have several styles and think one is hotter to wear... naturally it's the one with the best protection.
I decided to get a different suspension for each shade of shield; it's worth the ten or so bucks for the convenience, and the different styles of crown make it easier to tell the dark green and shade5 from each other.
Regards,
d