Iris recognition systems are biometric software and devices used to identify people by the unique structures of their irises. The system applies mathematical pattern-recognition to identify the iris of one or both of a person's eyes. Irises are unique to each individual, so they can be used, as an alternative to fingerprinting, to confirm their identity for the
purposes of authorisation and access control. A related biometric technique is retinal scanning, which attempts to identify individuals based on the unique patterns of blood vessels in their retinae. The following organisations offer software and hardware solutions for optical identification and iris recognition.