If you wear glasses you’re familiar with the hassles of dealing with the sun. You carry both your glasses and sunglasses wherever you go, switching back and forth each time you go outside and then head back in. One simple alternative is to wear glasses with photochromic or “transition” lenses. These special lenses darken in the sun then lighten when you go inside.
Photochromic lenses have been around for decades. Once, glass lenses were your only material choice and grey lenses the only color. But today’s photochromic glasses come in many materials and an array of lens colors. The most popular brand today is Transitions, but photochromic lenses are made by many manufacturers. Other brands include Sensity, Thin & Dark and PhotoFusion.
Photochromic lenses darken through different processes, depending on the type of lens and brand. The earliest glass photochromic lenses relied on silver chloride or silver halide to react to UV light and darken. Most of today’s photochromic lenses use proprietary dyes that undergo chemical changes that darken the lenses when exposed to UV light.