Hello, I'm not an optician; it would be great if somebody were as
friendly as to help me with the following question. (Let's assume
there's no need for any eye correction for simplicity's sake.) I
wanted to inform myself about how the "base curve" of an eyeglasses
lens affects the "intensity" in which the lenses are "bent", i.e.,
you all know there are may sunglasses that are "very bent", i.e.,
follow the shape of one's head for optimal protection. However
I found a couple of images where it said "base curve 4" or "6",
but I couldn't really get an idea which base curve means approx.
which intensity of "bending". All I was looking for was something
like:

[image of almost straight sunglasses lens] -> ~base curve xy
[image of medium bent lenses] -> ~base curve ..
[" " strongest bent lenses] -> ~base curve ..

just to get an idea, so-to-speak.

Would someone be as kind as to point me to some URL where I
can find out more, or enlighten me in some other way?

Thank you very much...

s.