So i don't really shed light on much of their relationship.

Eugene Vix aka Dr.Scorpio is the one that stole Issac Feel Goods Eye. Now if you notice usually when I draw Eugene it's with goggles. the reason for this is because he is hiding the fact that he had issacs eye implanted in his right eye socket. So he has oddball eyes. Ones is Red/orange the other is Issacs nice sky blue color. Issac does not know this. even when they do it Eugene always has his goggles on. Issac doesnt find out about this till way later when he asked to see Eugene face as a whole. Eugene is crazy I wont lie. His nickname before "Dr. Scorpio" was "The Ripper".