Pro Tip to Journalists: Keep Your Eye on Iris v. Retina

What is it about journalists and the human retina? I'd estimate that at least 95% of the time a journalist uses the term "retina" in association with biometric identity management modalities, they actually mean "iris". Does anybody know why this is?

After decades, ATMs still play key role in banking (Eagle Tribune - North Andover, MA)

He said tests are being conducted in Brazil on using biometric identification — scanning retinas or fingerprints — for ATMs. In Europe, he said, there are ATMs where customers can apply and be approved for a loan during their ATM sessions. “So the technology is there to do that,” Kerstein said.

You will never see a retina scanner in an ATM. As far as ATM deployments go retina is too expensive, and it takes too much time for people to get used to using it properly. Then there's the fact that if vascular biometrics are the answer, the hand/finger is cheaper and easier and if eye biometrics are the answer, iris is cheaper and easier. For ATM's the vascular/eye combo is overkill.

Iris (left) vs. Retina (right)

The iris (left), which gives people "eye color," controls how much light enters the eyeball. The retina (right) is the structure laying along the inside, back surface of the eyeball that translates light into nervous impulses for the optic nerve to send to the brain.

In a camera analogy, the iris would be, well, the iris, since cameras have them, too. The retina would be the film, or in an even better digital analogy, the charge-coupled device (CCD) that translates light into ones and zeros for computer chips.

Both iris and retina are used as biometric modalities in identity management applications.

Iris biometrics match the iris's unique surface features (similar to fingerprints). Retina biometrics use eye's vascular network for matching.

Retinas have been in use as a biometric identifiers for far longer than iris (1984 vs 1995), but using the iris is far more common today. This is because using the iris makes for cheaper and easier identifications.

For more on the subject, I recommend this (If you're a journalist, I can't recommend it enough!). It was written in 2006. Both technologies will have improved since then, but iris technologies have improved faster.