Fernando Meirelles sits in an office at a prison in Guelph, Ontario, Canada. "I was so afraid," he says. The director of the critically-beloved City Of God and the widely-respected The Constant Gardener is recalling the nausea of pre-production on his new film Blindness.

Meirelles had sought to adapt Jose Saramago's novel when it was first published in the original Portuguese in 1996. "I was a successful commercials director in Sao Paulo but my life was boring. I was having a mid-life crisis. In 2000, I decided I wanted to buy the rights and film it. But Saramago said he didn't want to sell."

Six years later, in June 2006, Meirelles took a call from Toronto-based producer Niv Fichman of Rhombus Media with the news that he had succeeded where Meirelles - and others including Diego Luna, Whoopi Goldberg and a few US studios - had not and won the blessing of the Nobel Prize-winning author. Fichman also had a screen adaptation of Blindness by fellow Canadian actor-director-screenwriter Don McKellar.

"There are thousands of directors in the world," says Meirelles, "and they approached me."

The story is an apocalyptic allegory: what would happen if everyone in the world went blind. How would the world look to a human race that could not see it' And what if only one person could truly see'

Meirelles was initially hesitant. Following The Constant Gardener he was looking forward to directing a reimagining of Shakespeare's Love's Labour's Lost from fellow Brazilian, writer Jorge Furtado. "But the coincidence was amazing. I was the first person to try to option the book and now it was being offered to me." Fichman and McKellar flew to Sao Paulo and the trio was at the 2006 Toronto International Film Festival to announce the film to buyers.

Julianne Moore and Mark Ruffalo were cast, the locations were set. But as production approached, Meirelles' euphoria passed. "If I could, I would have left. I had said, 'Yes, it's going to be great,' but then I started thinking about it and reading the book again... Oh my God." Meirelles switches to a different voice, "Here comes another film from Fernando. He did a good film so this one must be good."

Now, four weeks into production, with relocation to Brazil and Uruguay up next, Meirelles is feeling better. "I've seen some scenes, it works perfectly."

Focus Features International is selling the film overseas, while the producers retain US rights.