^ I should have noted that welding shades and glassblowing glasses also filter visible light heavily, of course (>90%). But what distinguishes them from sunglasses is the IR filtration. Glassblowing lenses also filter sodium flare, a glaring orange (visible) light emitted by some glass in a flame.

IR drops off adequately at spectating distances, and when I am at a demo, watching other people work, I don’t wear my glasses. Not sure about at a nuclear blast though.