I got this question:

Hello John,

Hope all is well. Here in Suriname all is ok. Busy. I'm now busy making a workshop and i am in need of some help. I cannot find it on the internet. Hope you can help me.
Case:
RS -6.50 C-1.25 ax 160
LS- 1.50 C-0.75 ax 180
Salesrep advised 1.67 material for right eye and 1.5 for left eye. That is impossible, as you know. (the thought behind this was: R-lens and L-lens could be equally thick now.)
Ok, so far the case. I want to explain to the group (45+ members) what happens if you'ld really sell this. In my mind, that is not a problem. What I am looking for is: an image where you can see a ray of light going through two different materials. Do you, by any chance, have such an image? And: would you be so kind to send this to me?

We have been going back and forth with it and I said I would toss it up here and see if we are lucky enough to grab an old-timer who can (really) explain why you would or why you could or why you would not or could not or should not.

Thanks