The musician is almost always seen wearing sunglasses. One of his eyes is not normally positioned, possibly deemed exotropia. He stated in an interview that at the age of two his uncle accidentally stabbed his eye with a fork.
These famous folks all have something in common . . . an imperfection, a defect or deformity. Some noticeable, some not so much. The main thing they have in common is they never let it stand in the way of success.