Photochromic lenses are eyeglass lenses that are clear when you are indoors and automatically darken when you are exposed to the sun.
Contact lenses can now be equipped with photochromic technology. Johnson & Johnson teamed up with Transitions Optical to develop Acuvue Oasys with
Transitions Lumino-Intelligent Technology, the first light-sensitive contact lenses on the market. These innovative contact lenses were launched in Canada in late March 2019.
How do photochromic lenses work?
The molecules responsible for darkening photochromic lenses are activated by ultraviolet radiation from the sun. Because UV rays penetrate clouds, photochromic lenses darken on cloudy days as well as sunny days. Photochromic lenses generally do not darken inside a vehicle because the glass in the windshield blocks most UV rays. Recent technological advances allow some photochromic lenses to activate with both UV and visible light, providing darkening behind the windshield. Ask your IRIS optician or optometrist for more details.
Photochromic lenses are available in almost any lens material and design. An added benefit of photochromic lenses is that they protect your eyes from 100% of the sun's harmful UVA and UVB rays. Since exposure to the sun and UV rays has been associated with the onset of cataracts at an earlier age, it's a good idea to consider photochromic lenses for your children's eyeglasses as well as for your eyeglasses. Polycarbonate is the safest lens material for children, offering up to 10 times the impact resistance of other lens materials.
Although photochromic lenses cost more than clear eyeglass lenses, they offer the convenience of reducing the need to carry a pair of prescription sunglasses with you everywhere you go.