Imagine maneuvering your car through a dark tunnel that bulges unexpectedly in places and then turns sharply through a maze-like passage. The perilous journey feels safer with a light and camera showing the way ahead. It’s even better if digital lines lay out a track, assuring you stay in your lane. In a rudimentary way, that scenario illustrates the advantage mixed reality (or augmented reality) is bringing to surgery, starting with the delicate pathways of the sinus.