(I'm saying "indirect path optics" because I don't actually know what this is called)
Modern optics aren't straight tubes of glass. They are generally either electronic, or take a indirect path to the crew. Otherwise, it's a weakspot. You don't really need to change it, since IFVs aren't that hard to penetrate in the first place, but if you want more realism, or even just better combat performances, you can either do electronic optics or indirect path ones that use mirrors.
Didn't stand a chance against my phone being thrown into the Pacific Ocean
update: added gunners sight
Flammenwerfer melts zis like nothing!
cookie_man: don't mind him when wants attention, he can't stop us or our saves! :D
help_what_im_doing: u r trying to make hate by bringing the topic again and again, I'll report u if u stir up an inappropriate argument.