Vasculitis is a rare auto immune disorder that can cause inflammation of the blood vessels, resulting in restricted blood flow.
He said it took him around a year to redevelop each sense and admitted, "You don't really appreciate it until it's gone."
"Until you go, 'I don't know if I'm ever going to be able to see again, I don't know if I'm ever going to be able to hear again, I don't know if I'm ever going to be able to walk again.'
"[I'm] lucky to be alive."
The That '70s Show star has since recovered from his illness and said it has made him approach life differently in that he no longer lets challenges stand in his way of success.
"The minute you start seeing your obstacles as things that are made for you, to give you what you need, then life starts to get fun, right?" he said.
"You start surfing on top of your problems instead of living underneath them."
The star has two children, Wyatt, 7 and Dimitri, 5, who he shares with his wife and fellow That '70s Show alum, Mila Kunis.
The couple made headlines last year after they suggested they don't regularly bathe their children.
The famous power couple told the Armchair Expert podcast co-hosts Dax Shepard and Monica Padman they don't wash them at all unless "you can see dirt on them".
"When I had children, I also didn't wash them every day," Kunis said. "I wasn't that parent that bathed my newborns – ever."
Kutcher agreed, saying there's no point if they aren't dirty.
"Now, here's the thing. If you can see the dirt on them, clean them. Otherwise, there's no point."
