BTW, clip on sunglasses suck....and not suck like a hoover...more like suck like a black hole. I had glare coming form the outside of the glasses lens, and from the inside of the sunglass clip-on lens....basically a giant glare loop...I could not see anyhting until I took em off.
So basically, if you have scrips, get a pair of prescription sunglasses, spend the dinero, it's bettter than clip on garbage that will leave you unable to see.