1. A method of biometric acquisition, comprising the steps of: (a) acquiring, by a sensor, at least one image of the iris comprising a reflection of a predefined geometrical shape; (b) determining a value of deformation or magnification of the geometrical shape in the reflection; (c) comparing the determined value to a value of deformation or magnification predetermined from a reflection occurring off a live eye; and (d) determining that the at least one image of the iris is acquired from a live eye if the determined value is consistent with the pre-determined value.