CORNWALL: See ‘t shalt thou never. – Fellows, hold the chair. –
Upon these eyes of thine I’ll set my foot.
GLOUCESTER: He that will think to live till he be old,
Give me some help!
[As Servants hold the chair, Cornwall forces out one of Gloucester’s eyes.]
O cruel! O you gods!
REGAN: One side will mock another. Th’ other too.

– William Shakespeare

King Lear, Act 3, Scene 7. In a particularly brutal scene Cornwall blinds Gloucester, whom he has branded a "traitor" – his betrayal being his support for and loyalty to King Lear. When Cornwall physically plucks out one of Gloucester’s eyes, Regan calls on him to pull the other one out too.