I emailed the Transitions people a while back about the life expectancy of the photochromic chemical in their lenses. They said 3 years, which is about the average time between prescription changes. If I can get 3 years, I'm happy.

 

Some scripts that require the use of a thick lens will not darken enough for real bright sunshine. Thats my case. So you may have to also have a pair of dark sunglasses for those days. I know I do.

 

I paid about $150 at rx-safety.com.........Transitions with my rx.........Scott