A 73-year-old man was blinded in one eye by a sucker punch in Brooklyn, cops and sources said Monday.

The victim, Gayman Hillaire, was walking near Kingston Avenue and Saint John’s Place in Crown Heights when he was slugged in the face by a stranger just after 11 p.m. Thursday, cops said.

The attacker struck Hillaire in the left eye before fleeing on foot, according to police sources.

Hillaire made his way to an area hospital, where the injury to his eye was determined to be permanent, sources said.