What makes the ultimate pair of sunglasses

It's that time of year in the United States - the peak of summer. The sun is at its strongest, and when you go outside on a bright day the urge to squint is instantaneous. With so many photons raining down from the sun, people definitely like to be wearing sunglasses.

But it brings up a question: which sunglasses should you wear? Is a $5 pair bought at a discount store just as good as a $150 pair bought at a specialty retailer? It turns out that the expensive pair of glasses really does have some advantages, which we can explore by looking at the ultimate pair of sunglasses.

Any pair of sunglasses starts with the lenses....