Someone should give you free cryptocurrency for a scan of your iris.
I'm not sure I'm 100% on board, but the tech is really interesting and their approach to privacy seems much better than I would expect from an offering like that. The aim is to be able to offer Know Your Customer using their identity platform to a mulititude of services.
Everest.org is their site
However, perhaps with training, identification could be made in spite of changes to the iris.
https://www.researchgate.net/figure/The-outline-boundaries-s...
Although that depends on the number of cameras around, access to them, and how much they are recording. Fingerprints are a lot simpler and easier to access.
Fingerprints can also be left on objects, which can be helpful for tracking someone.
Yes - I used one as far back as in 2010 on a science fair where we enrolled people to a research database.
A phone camera close-up should be enough in the right conditions, but additionally Samsung's Galaxy line used to include and iris scanner, which was just a near-infrared LED and a camera.
https://www.wired.com/2010/09/afghan-biometric-dragnet-could...
Of course, the Taliban were able to seize this collection of data.
https://theintercept.com/2021/08/17/afghanistan-taliban-mili...
Our irises are considerably more information-dense, accessible and stable over time as evidenced by the famous identification of Sharbat Gula: https://www.cl.cam.ac.uk/~jgd1000/afghan.html
A close-up photo should be enough to reliably identify a person years after they went missing.