Photochromic lenses that allow you to walk from inside to outside without putting on UV-filtering lenses have been around for decades. But the technology is just making its way to contacts.
Traditionally, these light-to-dark lenses have been constructed by coating a normal lens with a photochromic dye. When UV light hits the dye, the individual molecules expand, darkening the lens and absorbing light. Coating contacts, however, doesn't work so well.
So researchers at the Institute for Bioengineering and Nanotechnology in Singapore have laced contacts with a matrix on nano tunnels filled with these photochromic dyes. Not only has the … Read more