But an iris scanner doesn’t just take a picture of your eye to compare against whatever it has on record. In actuality, the procedure starts with a beam of near-infrared light directed at the person’s eye. This kind of light works better than visible light since it exposes the pattern of the iris much more clearly, thus making it easier for a camera to capture it. Besides, it allows the iris scanner to work in the dark. Prescription glasses and contact lenses (not colored!) do not block the beam either. Once the image has been recorded, an intelligent piece of software translates the iris’ pattern into code. This code is then compared against a record in search of a match.
What makes an iris scan unique?
The iris is the colored ring of muscle that opens and shuts the pupil of the eye like a camera shutter. The colored pattern of our irises is determined genetically when we’re in the womb but not fully formed until we’re aged about two. It comes from a pigment called melanin—more melanin gives you browner eyes and less produces bluer eyes. Although we talk about people having “blue eyes,” “green eyes,” “brown eyes,” or whatever, in reality, the color and pattern of people’s eyes is extremely complex and completely unique: the patterns of one person’s two eyes are quite different from each other and even genetically identical twins have different iris patterns.