My Gascan glasses were given to me with some weak amber tinted lenses, so I wanted to replace them with some polarized darker lenses.  I ordered these and they snapped right in, are crystal clear, and keep glare to a minimum. Another great thing about them is that they're very neutral shaded, so you're not going to be confusing any colors through them.

The only problem with polarized lenses is that sometimes they'll cut off visibility of electronic devices unless you rotate them.  But that's a small price to pay to have all that glare cut out.

I'm very pleased with them!