Neighbour Pat Knight said his wife heard screaming and crying from the house two doors down in the Abbottsfield community at about 10:30 a.m.
When he ran to the home near 120th Avenue and 36th Street, he saw the gate was open from the yard into the alley, Knight said.
He saw his 86-year-old neighbour, who is visually and hearing impaired, sitting on the ground and with his face bleeding saying, "Help me, I can't see."
His neighbour told him two men entered his backyard, demanded his wallet and attacked him with what he described as a meat cleaver, Knight said.
"We're as shocked as anyone," said Edmonton police Insp. Joel Whittaker at the scene.
Three men, who ran away on foot, were arrested nearby about 15 minutes later, he said.
Police could not confirm if the weapon used was a meat cleaver or whether the attack was random.
Police said they were called by the victim's wife, who was not hurt in the attack.
The man was taken to hospital by ambulance.
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