I don't see anything specific about the Quicksilver Madness but I'm pretty sure from this article that this effect pictured is created by using contact lenses. http://www.littlereview.com/getcritical/interviews/ventresc.htm
"I go to a whole new level of madness, and my eyes actually turn silver," groans Ventresca. "The contact lenses are the size of golf balls. The invisibility is a pain in the ass, but when I watch it, I really like it, and that makes it worth it. The genre supports experimenting that way. And it is so fun to play the madness."
The effects on the show were created using a combination of makeup, body suit and CGI effects according to this article as well. So the starting effect may be created with CGI ( a still shot of him looking at the camera while his eyes turn color) but the pictures like the shot you show are the actor wearing contact lenses.