My son is 12 years old he just had a foot surgery a week ago. The doctor prescribed oxycodone 5-325 MG T for pain. He is having blurry vision in his left eye and sometimes difficult in seeing out of the eye, it goes and come. I read that one of the side effects is blurry vision. He stop taking the pill 2 days ago, he was on it for 1 week. How long does side effects last of oxycodone and how long does it stays in the system of a child 12 years old? Thanks.