 The plot device of needles taped under the eye (an image featured prominently in the film's promotional campaign), came from a joke of Argento's.The director said it would annoy him when people would look away during the scary scenes in his films, and jokingly suggested taping pins under people's eyes so they couldn't look away from the film.The role of Signora Mara Cecova was written with Vanessa Redgrave in mind.