Checkout my new glasses! It's a transition lenses. In case some of you don't know what's a transition lens, it's a special lens that darkens when come in contaact with UV light. So, when I walk out into the sun, my glasses simply becomes a shades. This technology has existed for a long time. Only recent years have they improve it more. Like having it in high-index compressed glass and even having it flat. No more convex glasses that has a problem with wavy visions on the sides. These flat lenses actually got the concept from flat screen TVs. Amazing, right!