Biometric eye scan. Conceptual computer artwork of the scanning of a human eye. Iris scanning images the iris, the coloured part of the eye, which is unique in each individual. Retina scanning does the same for the retina, a light-sensitive neural membrane inside each eye, and accessed through the pupil (black, centre right). The varied structure of the iris (green/blue) is seen surrounding the pupil. In both cases, a computer divides the scan into areas from which it recognises unique features. The data can be used to identify people, a process known as biometric identification. Other forms of biometrics includes fingerprints. Zeros and ones are used in computer binary code.