Power Word Blind

You utter a single word of power that causes a creature to become blinded, whether the creature can hear the word or not. The duration of the spell depends on the target's current hit point total. Any creature that currently has 201 or more hit points is unaffected. For 50 or less HP, the effect is permanent; for 51–100 HP, the duration is 1d4+1 minutes; for 101–200 HP, the duration is 1d4+1 rounds.