Photochromic or Photochromatic Lenses are those which darken automatically when exposed to the Sun rays. These are specially designed to adapt under various lighting conditions and hence, are also famous as light-adaptive lenses or self-tinting lenses. Offering both protection and comfort, photochromic lenses are a perfect solution for spectacle-wearers who are always on the go and keep moving indoor & outdoor.
Photochromic lenses are made using special carbon-based molecules which react to UV rays. These molecules absorb the rays & make the lenses turn darker. However, this might not be instant as intensity of darkening of the lenses depends upon the intensity of UV rays. The more the UV rays are, the darker the lenses will be and vice versa. Once you come back indoor, or at night, the darkness will fade away and you’ll have your clear lenses back without physically changing your frames.