Fernando Meirelles did boys with guns in "City of God" and murderous corporations in "The Constant Gardener." With "Blindness," the opening night entry at the Cannes Film Festival, the Brazilian director exposes the world's ultimate savages: your friends and neighbors.

A terrifying fable about how low people might go to stay alive when a plague of blindness turns them into helpless internees, "Blindness" presents an unnerving reflection of real tragedy and bureaucratic heartlessness, from Hurricane Katrina to global food shortages to the cyclone in Myanmar, where the military government has severely restricted relief efforts.

"There are different kinds of blindness. There's 2 billion people that are starving in the world," Meirelles said in an interview Thursday, a day after the film's Cannes premiere. "This is happening. It doesn't need a catastrophe. It's happening, and because there isn't an event like Katrina, we don't see."

Opening in U.S. theaters Sept. 19, "Blindness" is adapted from the novel by Portuguese author Jose Saramago, winner of the Nobel Prize for literature.

The film chronicles the panic, disorder and barbarity that erupts after a contagion spreads "white blindness" throughout an unspecified city, with people's vision replaced by a milky cloud.

Victims are crammed into decrepit, filthy wards and left on their own, with no medical care. Scant food is provided, and trigger-happy soldiers gun down anyone they think might make a break for freedom, though all the afflicted can do is stumble about aimlessly.