On Tuesday night's episode of America's Got Talent, a 16-year-old boy from Long Island earned the coveted Golden Buzzer from judge Howie Mandel for his rendition of The Jackson 5's "Who's Lovin' You." Before his audition, Christian Guardino opened up about undergoing an experimental treatment that gave him back his sight after he'd been blind for most of his life. He can now see well enough to read enlarged notes on sheet music.