This hollow iron sphere is inscribed with an eye-like iris, and a brass hinge and clasp allow it to open. You can use an action to hold the open oculus to your eye and speak its command word. Your eye is drawn into the sphere, leaving an empty socket. While your eye is trapped and you are holding the oculus, you have darkvision out to a range of 120 feet, and can detect polymorphed and shapechanged creatures and objects within 120 feet. You can use another action to return your eye from the oculus.