Blind Trust: You can enter a meditational state when pressing <F>. When you're in the meditational state, you're blind but able to see objectives auras on 10/15/25/35m and the Killers Aura in a 5/7/9/13m range. Return your sight in 10/8/5/3s.
Find more perk info out here: Perks
"I trust the darkness, do you?"