There is no need to use lights.
The darkness presses all around you, runs through you, toys with your mind and ensnares your sense. But it is unable to do much to you. This mere darkness.
However, it wouldn't take a real horror hiding within it to cause panic. The thing you really fear is your mind. The dark shape in to corner is merely a denser shadow. However, to the active and fearful brain, it is a vicious murderer, crouching, ready to pounce. Or else a ghost, ready to leap out and shriek to the high heavens. But it is none of these things. It is simply emptiness.
That's where I am now. In the darkness. I don't know where I am. I could be in a vast desert, or a forest, or atop a high mountain. But none of these things matter, for truly I am in prison. The most complex, intricately fortified prison, so labyrinthine that it holds no need for alarms or guards.
Who needs walls and weapons to hold men, who are already trapped in their own heads?