Eyes as mouths

With special dedication to Boson.



The main difference between eyes and mouths is the fact that eyes don't have teeth (which, fun fact, are made from changed skin just like any hair on your body) and eyes take in the distant signal. Your tongue also can feel tastes even after you drink or eat something that is really bitter (bitterness is the taste humans feel most strongly.)

Main similarity is the fact they both make an enzyme that breaks down bacteria - lysozyme. The iris is a muscle just like your lips and they work quite similarly, making the hole in the middle bigger or smaller as needed (the pupil is that hole in the eye).

The eyes can't be used to get information about chemical makeup of something and mouths can't detect individual electrons. They take different types of information in.

Eyes aren't able to get anything that would give energy from the outside. Mouths can chew and swallow plant and animal matter to get energy. The saliva begins to break down sugar, but eyes just send whatever they got to the brain to make the sense of.

Mouths don't see any fake signals, nor can there be any subliminal message put in a taste. 

I would not necessarily make the connection between mouths and eyes. I would make a connection between tongue membranes which detect chemical signals and retinas which detect photons.