When i made the glasses for the model of Rei, i was getting worried because despite they being flat like real life glasses, the didn't looked good on all camera angles. Then i just saw that animators and artists just bend the glasses how they see fit depending on the angle of the camera/character head
@rick mine's are flat, but i've seen that they can adjust the bent a bit to adjust them better to your head shape to be more comfortable
@rick yeah! sometimes the profile of the anime faces is very snouty, you don't note it at first but when you inspect it carefully it looks even kinda ridiculous.
@rick now compare these camera angles to the change of the curvature of the glasses... it's laughable