The colorblind simulator I found a while ago is a godsend, really helps with figuring out an approximation of how Stewie sees the world, and how some shades of blue and purple may as well be the same thing with his Protanopia/Red-Blind vision. Luckily the goggles already lock on to Monsters and it’s even easier to set things up for Red-Blind cats. With the added bonus of making Stewie’s eyes just a bit more yellow than normal while wearing them (boy that’s gonna be fun to remember)