IMC a character did exactly this. His new eye though, did not allow her to see through it. It instead made him see the worst in everybody and everything. He got advantage on seeing through peoples lies, when he eventually discovered that he thought it was great, but as a DM I would describe everything to him in the most suspicious way possible "e.g. The little girl is playing with her dolly, she quickly glances at you when she thinks your back is turned, and catch a glimpse of a cunning intellect beyond a mere child, she smirks slyly and sings to her dolly in an eerie tone, you notice the doll is flayed in places."
In essence, a smile becomes a smirk, a glance becomes a glare, a slight pause in conversation becomes a troubled silence etc.
In essence, a smile becomes a smirk, a glance becomes a glare, a slight pause in conversation becomes a troubled silence etc.