http://www.luxist.com/2010/07/14/tag-heuer...optics-and-pur/

the description seems to fit nicely with what SR4 terms as "vision enhancement", as its more about improving contrast then about amplifying light.

Not too expensive if they work, but then good ol' shooting glasses have similar effects and a lot more options since they've been around longer.

Unfortunately, I can't wear those tinted-yellow or tinted-brown sunglasses. They wash the color out of my vision, like standing under a sodium-lamp.