Acute Senses (1): One of your five senses is incredibly sharp, and detection rolls involving this sense have a -1-2 difficulty. You must buy this merit separately for each sense.
Nightsight (3): You can see in near-total darkness, and so your difficulties for being in a dark area are reduced (or nonexistent). You may, however, be sensitive to bright light, and sudden bright light may dazzle you for a turn or two.