Complex sentence: He initially came to the United States at the age of 11 to treat pathologic nystagmus, an involuntary movement of the eyes, during a trip to Disneyland, Apl expressed his interest in staying in the United States.
Split into simpler sentences: He initially came to the United States at the age of 11 to treat nystagmus, an involuntary movement of the eyes. During a trip to Disneyland, Apl expressed his interest in staying in the United States.