I haven't found one as yet with it "inbuilt" as part of the...

I haven't found one as yet with it "inbuilt" as part of the actual biometric itself like WBT. Not to say there isn't one - I just haven't found it yet.

It is primarily because the tear film on the cornea changes each time creates an ability to confirm the image is from a live subject as I interpret anyway -

Brownian Motion:

The random movement of microscopic particles suspended in a liquid or gas, caused by collisions with molecules of the surrounding medium. Also called Brownian movement.

Most other systems I have found are studying various other methods of "liveness" and trying to implement such as blinking, or using eye / hand veins (blood movement / changes), heart beat, flashing light to dilate the pupil, keystrokes, gait (phys movement) and so forth.

That is part of the reason a lot of existing tech can be spoofed - they have difficulty proving the person presenting is alive hence HD eye pics or gummy bear fingerprints can b used to access...lol

Obviously liveness can be implemented in some way or form but is always a trade off against what is the most accurate or secure biometric (which appears to be iris primarily) or most commercially accepted (fingerprint?), then increasing that to fusion (multi-modal / multi-biometric) and being able to keep cost down, rewriting algos to be able to detect liveness + the biometric parameter, being able to have hardware (if needed) to detect it plus considering the surrounding enviro (lighting, reflections etc.) that may affect the method.

Lots of considerations from what I've read hence why I do like the WBT "inbuilt liveness" - no naffing about other issues / methods / add ons.

WBT have corneal/iris fusion they say, they have liveness, they have visible wavelength, they have one time pin, they have spoofing covered (so far anyway until proved otherwise) and all in a single pass, single sensor it would seem......what's not to like IMO - always risk but does WBT mitigate some /most of this....for me....yep.

I'm just waiting to read final chapter coming up and what will b will b