I don't know anything about the glasses sold on the site, but this is a pretty good test for colorblindness--a lot of people aren't aware they have it, so not a bad thing to check out before you choose sunglasses:
https://enchroma.com/pages/test
I didn't know I had it until I was in my 20s--mild color blindness is not something you'd likely notice until it either was picked up by testing or you missed an important visual cue---nothing that isn't gray appears gray to me, for example. It's a matter of lowered contrasts.