Sight Lens is a Power Perk introduced in Futuristic Zombies as an original perk.
The icon is represented by an eye. In its pro form, the icon gains a bright red glowing outline.
Overview
Sight Lens allows the player to Mark an enemy for 5 seconds when aiming down sights on them for one second, which reveals that enemy to allies and causes the Marked enemy to take increased damage.
After killing 15 Marked zombies and having allies kill 10 Marked zombies, the perk becomes Sight Lens Pro. In its pro form, enemies that are Marked are now revealed for 10 seconds to allies, and Bosses who are Marked now take increased damage.