Autocraft Eyeglass Clip

Q:

I cannot wear normal sunshades due to the fact that I wear corrective lenses. I have recently purchased a pair of flip down shades that clip on at the far left of each eye. They have a straight bridge over the nose as well. I am wondering if the eyewear clip will work for me? I called my local store which told me this would not work. She explained that they clip on the temples going to the ears. After thinking about her answer, I don't understand why I can't clip it onto the bridge across the nose. I would greatly appreciate if you are able to explain the hows and whys of whatever answer you give.