Records of the Three Kingdoms
Xiahou Dun, courtesy name Yuanrang, was from Qiao in Pei, a descendant of Xiahou Ying and a clansman of Cao Cao from the same district. He joined Cao Cao at the start, held important commands, and also oversaw the rear. In the war with Lü Bu a stray arrow struck his left eye. The army called him the blind Xiahou. He hated the name and would smash a mirror when he looked into one.
He was harsh, and he also brought teachers into the army to read the classics. After Cao Cao’s death, when Cao Pi became king of Wei, Xiahou Dun was made grand general. He died of illness within months. Cao Pi mourned him in plain clothes at the east gate of Ye. Pulling the arrow out and eating the eye is not in the biography. The biography has the arrow, the lost eye, and the hated nickname.
Romance of the Three Kingdoms
The novel has Cao Xing shoot Xiahou Dun in the left eye. Xiahou Dun pulls the arrow, and the eye with it, says flesh and blood from his parents must not be thrown away, swallows it, and kills Cao Xing with his spear. That scene is his mark in the book.
Afterward he appears as the one-eyed general in Cao’s lines until he sickens and dies not long after Cao Cao. Swallowing the eye is the novel’s addition.
Reference: Wikipedia · Xiahou Dun