Aging doesn’t affect the distinguishing characteristics of the average person’s iris for almost a nine-year period, according to researchers investigate the use of iris recognition for biometric identification, InformationWeek reports.

This research, reported by the National Institute of Standards and Technology (NIST), suggests that identity program managers may not need to recapture iris images as frequently as generally thought to maintain recognition accuracy.

Read more: The Most Influential Cyber Security Team (Hint: It's part of NIST.)

The NIST researchers based the study, Temporal Stability of Iris Recognition Accuracy, on two vast data sets, including one of nearly 8,000 frequent travelers across the Canada-U.S. border that involved millions of captured iris images, the article says.