For years, debate over the potential effect of ageing on iris characteristics has divided some members of the biometrics research communityA biometrics-specific journal now plans to publish opposing reports on the topic in the spirit of encouraging productive discussion.The special edition of research journal IET Biometrics will feature two key papers in this area from authors with very different views on the topic.One of the contributions is written by Estefan Ortiz and Kevin W Bowyer of the University of Notre Dame. It is called “A critical examination of the IREX VI results”, and reviews a report published originally by the US National Institute of Standards and Technology (NIST).The original NIST report looked at 3.5 million iris images from over 600,000 persons collected in an operational system over a period of about six years and found no evidence of an iris ageing trend.As noted in a statement from IET Biometrics, the Ortiz/Bowyer paper argues that improvements in the methodology used in the NIST report would lead to an uncovering of an ageing trend leading to a decrease in recognition rate over time.The second paper (written by Patrick Grother and James Matey, two authors of the original NIST report) is “IREX VI: mixed-effects longitudinal models for iris ageing”.This paper argues that “the large 'ageing' effects claimed by UNDߪare the result of lack of control of ambient conditions during their data collections and do not represent changes in the underlying iris pattern”.IET Biometrics Editor-in-Chief Professor Michael Fairhurst points out that: “These contributions thus provide informed and well-argued position statements presenting different views of this issue, offering not only a broader perspective on the question of the effects of ageing in respect of the iris, but providing a perspective which is relevant to the wider issue of template ageing in biometric systems.”This is an area of such importance and current debate that it is considered timely to make these two papers ߪ more generally available to the wider scientific community, as a means of furthering our understanding of this issue and encouraging better informed debate”.