Term: Low-Light Vision

Brightness

Vision that is not hindered by lower light, often a result of adapting to the reduced brightness. It allows for the creature who has it to see fine in what is considered dim light.

During periods of Darkness, effects that give off light (often having the Brightness trait) will give an emanation of light in a radius, often Bright Light and then Dim Light. Low-Light Vision doubles Dim Light for the creature.

To that end, if a torch were to give 10 ft of bright light and 10 ft of dim light, the creature with Low-Light Vision would see 30 ft in the darkness.