In this paper we present a study on visual perception, awareness and self-control, based on the visual exploration of the classical Brentano-Muller Lyer illusion and of some of its variants. The study has been realized with the help of self-made software designed to analyze eye-tracker recordings. In the case of subjects that have a certain familiarity with visual illusions, although not with all its variants, it is possible to observe, after some hundreds of milliseconds, the occurrence of a transition toward an aware exploration of the images. Moreover, it has been possible to show that the awareness might or might not help - it depends on the subject - to get out from the "trap" of the illusion.