  This paper presents the most comprehensive analysis of iris recognition
reliability in the occurrence of various biological processes happening
naturally and pathologically in the human body, including aging, illnesses, and
post-mortem changes to date. Insightful conclusions are offered in relation to
all three of these aspects. Extensive regression analysis of the template aging
phenomenon shows that differences in pupil dilation, combined with certain
quality factors of the sample image and the progression of time itself can
significantly degrade recognition accuracy. Impactful effects can also be
observed when iris recognition is employed with eyes affected by certain eye
pathologies or (even more) with eyes of the deceased subjects. Notably,
appropriate databases are delivered to the biometric community to stimulate
further research in these utterly important areas of iris biometrics studies.
Finally, some open questions are stated to inspire further discussions and
research on these important topics. To Authors' best knowledge, this is the
only scientific study of iris recognition reliability of such a broad scope and
novelty.
