Iris recognition technology is used to identify individuals by photographing the iris of their eye. It falls under a category of technology known as biometric-based authentication, also called biometric security. Iris recognition technology has become popular in security applications because of its ease of use, accuracy, and safety. Its most common use is controlling access to high-security areas.

Iris recognition technology works by combining computer vision, pattern recognition, and optics. First, a black-and-white video camera zooms in on the iris and records a sharp image of it. The iris is lit by a low-level light to aid the camera in focusing. A frame from this video is then digitized into a 512 byte file and stored on a computer database.

Iris recognition technology is capable of recording this image from as much as 16 inches (40.64 centimeters) away, so no physical contact is necessary. An individual's identity can then be confirmed by taking another picture of their iris and comparing it to the database. Iris recognition technology can confirm someone's identity within a few seconds.

Glasses or contact lenses do not interfere with the operation of iris recognition technology. Very few surgical procedures involve altering the iris, in which case re-enrollment in the database would be necessary. Blind people, as long as they have an iris present to scan, can likewise be identified with iris recognition technology.

Iris recognition technology offers the highest accuracy in identifying individuals of any method available. This is because no two irises are alike - not between identical twins, or even between the left and right eye of the same person. Irises are also stable; unlike other identifying characteristics that can change with age, the pattern of one's iris is fully formed by ten months of age and remains the same for the duration of their lifetime. Iris recognition technology is also accurate because it uses more than 240 points of reference in an iris pattern as a basis for a match. By comparison, fingerprints use about 60.

Iris recognition technology is currently used at physical access points demanding high security, such as airports, government buildings, and research laboratories. However, some hotels have experimented with using iris recognition technology in place of a room key. The potential exists for iris recognition technology to replace most current forms of physical access-based identification. This would include anything requiring a password, personal identification number (PIN), or key; such as electronic transactions, building access, or automobile ignition. And unlike those physical methods of identification, an iris cannot be stolen. Iris recognition technology addresses the problems of both password management and fraud.