I remember those things. On a lark, I took a cheap pair of
   prescription glasses I got from zenni optical years ago ($20 -
   way better than the $400 I was used to paying), and dyed them in
   RIT yellow die. Worked perfectly! Everything worked just like
   the yellow sunglasses did - (I think the ones I had long ago
   were called "Blublockers or something that fit over my glasses..
   made me look like I had glaucoma, everybody said... whatever -
   had to stop wearing them) Same thing happened with the yellow
   lenses. Worked great - didn't care how it looked. Ppl I was with
   cared how it looked. So, I just got some forest green dye and
   then ended up a lovely brown color, totally socially acceptable
   and yet retained the blue blocking abilities of when they were
   yellow. Always experimenting with something weird.