PORTLAND — A Portland man is undergoing surgery and could lose his sight after being attacked outside his apartment building early Tuesday morning.

Edgar Stockdale, 57, was outside 100 State St., an elderly housing complex, having a cigarette when a man he knew, Richard Gregory, 61, walked up to him and started rambling about war and al-Qaeda, police said.

Stockdale gave Gregory some cigarettes and prepared to go inside when Gregory pushed him down then got on top of him and started punching him, police said. Gregory then pressed his thumbs into Stockdale’s eye sockets, police said.

A witness called police and officers found Gregory standing over his victim, police said. Stockdale was already blind in one eye before the attack. He’s scheduled to undergo surgery Tuesday to try to save the sight in his other eye, police said.

Gregory is being held on $5,000 bail at the Cumberland County Jail on a charge of aggravated assault and is under observation for mental health problems.