I think it should be a trait at creation, and unremovable in game.
Jaunty Eyepatch: You don't just wear an eye patch, you wear it well: -2 PE, +2 CH
Oh, that's an awesome one!

But I don't think it should be unremovable, you should just get one in your inventory which you can equip and unequip as you like. Unequipped you see that you have a white eye, and you won't get the Charisma bonus though you still get the Perception penalty. Put it on, and you look good! Like with the Four Eye trait where you need to wear glasses to get a Perception bonus, and without them on you get a Perception penalty.
I hope there are more like these actually!

Handicaps that actually force you to wear something special to get a bonus.