A mask or helmet or any such wearables is mostly used for protecting one's head from injury or in this case protects one's identity. But for Spider-Man as depicted in *Captain America: Civil War* and *Deadpool* the eye part in the mask actually seems to move according to the eyes.

Why does the eye part of the mask move and how? Isn't a mask kinda fixed stitched material? How does it track the eye reaction which the hero makes inside the mask?