RIO DE JANEIRO, Brazil — Antonio Rodrigo Nogueira’s life and career have always been an example of perseverance, coming back from impossible situations both in and out of the ring and cage. But one of the adversities he has faced throughout his entire life was kept a secret from the public for decades.

Until now.

The former UFC and PRIDE heavyweight champion and UFC Hall of Famer held an event for media and special guests Wednesday night in a restaurant in Rio de Janeiro, Brazil, airing a documentary about his life that will premiere in the coming weeks on Brazilian television. In the documentary, “Minotauro” talks for the first time about a right eye injury that has bothered him since he was a young kid.

When he was four years old, seven years before a truck ran over him and almost killed him, leaving him hospitalized for almost a year, Nogueira was hit in the eye with a pair of scissors and never fully recovered his eyesight.

“I had six surgeries when I was a kid, two when I was teenager, and two recent ones,” Nogueira told MMA Fighting. “I implanted an intraocular contact lens, and if you poke me in the eye really hard it moves. Imagine how many punches I took… I had to put it back in place all the time.”

One of the fights where his eye injury was a big issue, he says, was against Mirko Cro Cop for the PRIDE interim heavyweight championship in 2003. Nogueira was hurt multiple times and knocked down a left kick in the final second of the opening round, but was able to come back in the second round and win with an armbar.

“It was a problem in some fights,” Nogueira said. “This fight with Cro Cop I couldn’t see anything with my right eye.”

Nogueira, who retired from the sport in 2015 with a 34-10-1-1 record, says he had to undergo surgery two months before one of his MMA fights, but was always able to pass the medicals before any bout.

“It was two fights: the fight itself, and the fight to be able to see,” Nogueira laughed. “That’s one of the reasons why I stopped fighting. My last fight, with (Stefan) Struve, he poked me in the eye several times. If you watch the fight, I’m trying to secure a single leg and he putting his fingers in my face, and that disturbed me a lot. That’s one of the reasons why I stopped fighting because it hurt a lot.”

Nogueira, who now works for the UFC as an executive and ambassador in Brazil, hung up his gloves following losses to Struve, Roy Nelson and Fabricio Werdum. His legendary career includes wins over Randy Couture, Tim Sylvia, Josh Barnett, Dan Henderson, Fabricio Werdum, Mark Coleman, Bob Sapp, Brendan Schaub, Heath Herring, Ricco Rodriguez, Semmy Schilt and many others.