Eyeglasses and Eyewear
Transitions and Photochromic Lenses
Photochromic lenses such as Transitions contain molecules that darken when exposed to ultraviolet light and clear when it is removed. One pair serves as both glasses and sunglasses.
Photochromic lenses suit Arizona well. Moving between blazing sun and air conditioned interiors many times a day makes switching between two pairs of glasses tedious, and a lens that adapts on its own removes the decision entirely.
The mechanism is UV activated. Molecules embedded in the lens change structure when they absorb ultraviolet light, darkening the lens, and revert when the UV goes away. Darkening takes under a minute; clearing takes several minutes longer, which is why walking indoors leaves you briefly in sunglasses.
The limitation worth knowing before you buy is driving. Most car windscreens block the majority of UV, so photochromic lenses darken far less behind the wheel than they do outside. Some designs respond to visible light as well to address this. If driving comfort is your main concern, dedicated polarised prescription sunglasses do the job better.
What this does not do
- They darken less in a car because windscreens block most UV.
- Clearing indoors takes a few minutes.
- Cold slows the reaction, which matters little here.
- They are not polarised unless specifically ordered as such.
Questions and answers
Do they work in the car?
Not fully. Standard photochromics rely on UV, and windscreens block most of it. Some designs also respond to visible light. For driving specifically, dedicated polarised sunglasses perform better.
How fast do they change?
Darkening takes under a minute. Clearing takes several minutes longer, which is why there is a brief adjustment period on walking indoors.
Are they polarised?
Not by default. Polarised photochromic options exist and are worth asking about if reflected glare is your main problem.
Do they wear out?
The effect gradually weakens over years of use. Most people replace lenses on prescription change before that becomes noticeable.
Talk to someone about transitions and photochromic lenses
Appointments are scheduled two per hour, so there is time to answer questions properly. Call (480) 706-3937 or request a time online.