John of God grabs what looks like a kitchen knife from a silver tray and appears to scrape it over the right eye of a believer.

The "psychic surgeon" then wipes a viscous substance from the blade onto the patient's shirt.

The procedure is repeated on the left eye of Juan Carlos Arguelles, who recently traveled thousands of miles from Colombia to see the healer.

For 12 years, Arguelles says, he suffered from keratoconus, which thinned his cornea and severely blurred his vision.

John of God is Joao Teixeira de Faria, a 69-year-old miracle man and medium to those who believe. He's a dangerous hoax to those who do not.

For five decades he's performed "psychic" medical procedures like that for Arguelles. He asks for no money in exchange for the procedures. Donations are welcomed, however.

The sick and lame who have hit dead ends in conventional medicine are drawn to Abadiania, a tiny town in the green highlands of Goias state, southwest of the capital of Brasilia.

Faria says he's not the one curing those who come to him. "It's God who heals. I'm just the instrument."

"Psychic surgeons" are mostly concentrated in Brazil and the Philippines with roots in spiritualist movements that believe spirits of the dead can communicate with the living. Like Faria, they often appear to go into a trance while doing their work, allowing God, dead doctors or other spirits to flow through them.

Such practices have been roundly denounced.

The American Cancer Society has said practitioners of psychic surgery use sleight of hand and animal body parts during procedures to convince patients that what ails them has been snatched away.

But Arguelles, the 29-year-old Colombian who had his eyes worked on by John of God, doesn't care what the medical establishment says.

A week after visiting Brazil and undergoing the procedure, he said his vision had improved "by 80 percent" and was getting better each day.