Samsung recently introduced its new Galaxy Phone with Iris scanner, but much more interesting than new phones is the work of Adam Czajka and Piotr Maciejewicz Dead eye biometrics have explored. You have now found out that eyes were still recognized 5 hours after death, in individual cases up to 27 hours.
They used both infrared and visible light cameras to collect images, getting the first set at 5 hours after death, and doing two other sessions at about 16 and 27 hours after death. Czajka and PhD student Mateusz Trokielewicz then tested whether several commercial products and one open-source iris matching system worked on the dead eyes.
He found that the dead eyes were easily recognizable in the first session, and some could still be used for identification as late as 27 hours after the person's demise. While the cornea gradually became cloudy over time as the corneal cells broke down, that opaqueness didn't interfere with the infrared imaging. Czajka's now conducting research using eyes that are several days or even weeks past their expiration date.
Paper: Postmortem Human Iris Recognition, from the conclusions:
This paper presents the only study that we are aware of regarding post-mortem use of human iris as a biometric identifier. Contrary to claims common in the biometric community, our results show that human iris can be successfully employed for biometric authentication for a number of hours after death. Empirical study incorporating four different iris recognition method has shown that a significant portion of iris can be successfully recognized 5-7 hours after a person's demise (with FNMRs equaling 0% to 8.33% for the best and the worst performing method, respectively).
However, this percentage is expected to decrease significantly as time period since death progresses, reaching FNMRs of 26.67% to as much as 86.67%. Comprehensive medical commentary is also presented to explain the underlying causes of such behavior, with processes associated with corneal opacification, drying and loss of intraocular pressure recognized as the most probable sources of recognition errors.