Are photochromic lenses right for me?
When you’re purchasing new lenses, ask about photochromic lenses. “Photochromic” comes from the Greek word photo, meaning “light,” and chroma meaning “color.” Transliterated – “light-color” – photochromic lenses will darken when exposed to ultraviolet light.
Sometimes known by the brand name “Transitions,” photochromic lenses are an outstanding option for those who are constantly on the move. Photochromic lenses will provide sun protection while outdoors, and be clear indoors.
Carl Zeiss has a new photochromic lens called PhotoFusion, which darkens twice as fast as their previous models, while remaining 93% transparent in their clear state.
Photochromic lenses contain a chemical that will unfurl (much like an umbrella) when exposed to ultraviolet light. It is this expansion that creates the darkening of the lenses.
What are the disadvantages? Those of you spending most of your time driving should invest in a pair of dedicated, polarized sunglasses rather than photochromics. The reason is that your windshield will attenuate a majority of ultraviolet light, which prevents the lens from reaching maximum darkness (if it darkens at all). Serious drivers will find this troublesome.
To address this problem, Transitions brand of photochromic lenses offer the Transitions Extra Active. These will darken in the car, but will remain lightly tinted in the their clearest state.
Discuss these options when you’re working with your optician!