SAN FRANCISCO -- With iris security identification recently in the news, the American Academy of Ophthalmology explained how an eyeball can be substituted for a passkey or a fingerprint.
"The iris is distinctive to each person," said Academy member Ivan Schwab, MD, professor of ophthalmology and director of cornea and external disease service at the University of California at Davis. "As such, the iris can be used to confirm someone's identity."
The complicated form of the iris is what makes each one different. There is a pupil, a ring immediately around the pupil, an even larger ring beyond but still around the pupil, and rugae -- folds, hills and valleys in the iris structure.
While passwords can be hacked, passcards can be lost, and other personal identifiers can be compromised, the iris is nearly impossible to alter. Fingerprints can be manipulated with exposure to chemicals, makeup or even dust, but it would require an ophthalmic surgeon to change an iris.
"The iris as a form of I.D. has the advantage of portability, and it cannot be forgotten, lost or hacked," Dr. Schwab added. "And contrary to the way it is described in a recent fictional bestseller and several Hollywood blockbusters, the eyeball must be attached to a living person for the technology to work. Without blood supply, the retina would not have the same appearance, and the pupil would be hard to dilate."
Although comparable to the reliability of a fingerprint, the iris may experience structural changes during a person's lifetime. Limitations to the technology may include disease, injury, loss of the eye and age.
There is no apparent danger to the eye being scanned.
