American actor Ashton Kutcher has revealed that, three years ago, he fought a "weird, super rare form of" an autoimmune disorder called Vasculitis. The disease "knocked out" his vision, hearing and equilibrium, Kutcher said, adding, "(I'm) lucky to be alive." The 44-year-old 'That '70s Show' star said it took him around a year to build his senses back up.