Number one, that's fanart dude, it's not real proof of a theory. Number two, nice theory, but you need my proof. Number three, my theory is that riku wears a blindfold to increse his other senses. If you play rerevse rebirth on CoM, they are always talking about how they can smell the darkness and etc. Now at the begining of r/r only Zexion said he could smell the darkness and pick up other peoples scent. But as you progressed Riku started to do it to. Not only could he smell darkness, he could taste it in the air, smell danger, and pick up peoples scents. So that makes my conclude that that's why he wears the blindfold.