In one of the most grisly scenes in all of Shakespeare, Gloucester's eyes are gouged out.

Cornwall tells Edmund to leave the room so that he will not see what they are going to do to his "traitorous" father. It is clear from this statement that Cornwall believes Gloucester to have betrayed them and, therefore, to be fit for a terrible punishment. Cornwall then sends Goneril off. He states that he cannot legally pass the death sentence on Gloucester but can express his "wrath," which men can "blame" but not "control." In other words, Cornwall plans to act with great cruelty merely because he can get away with it.

Gloucester is tied to chair and confesses that he helped Lear head to Dover to meet up with the French army that has landed with the hope of retaking England for Lear. Gloucester says he had to get Lear away from his daughter Regan out of fear she would "pluck" his eyes out with "cruel nails" and fear that Goneril would sink her "boarish fangs" into his flesh.

Cornwall then gouges out one of Gloucester's eyes and steps on it. A servant tries to defend Gloucester by stabbing Cornwall and is killed by Regan, who says mockingly that Cornwall should take out Gloucester's other eye to even up his face. Cornwall then plucks the "vile jelly" out of Gloucester's other eye.

This act of wholly unnecessary sadism shows graphically that the wrong people have been given power and that it has gone to their heads in excessive ways. Labelling someone who has made him angry a traitor allows Cornwall to cross all bounds of decency because he knows nobody can stop him.