[masraum]

Originally Posted by Dantilla

As I understand it, the older Photogray glass lenses reacted to light.
The newer Transitions on plastic lenses react to UV, which is partially blocked by auto glass.
That's why the newer lenses will not get as dark in a car as if outside in direct sunlight.

I really like my Transitions, but also keep a pair of "real" prescription sunglasses in the car for when driving directly towards the sun.

beat me to it.