My cat is ten years old. When we noticed the first spot he was two and when he was four the whole iris was covered with spots. His eyesight is perfect and he is very healthy. Take Picasso to a vet but do not have his eye removed!. I don't think so, but if he gets very ill one day then you can decide on what steps to take. And in reply to ssome comments, some cat breeds have different coloured eyes from birth. It is a trademark! Happy long years with Picasso.