3.5 out of 5

Clear : Verified Identity Pass

Clear uses biometric (fingerprint and iris image) verification to confirm each member’s identity. This includes advanced finger-scan technology, as well as non-invasive iris imaging.

Clear is working on a second generation kiosk featuring state-of-the-art technology developed by Clear and General Electric that is being tested by the Transportation Security Administration (TSA).

Clear expects to unveil shoe-scanning technology as soon as it is approved by TSA, which will enable Clear members to leave their shoes on during security screening.

http://www.flyclear.com/how/how_technology.html

Currently available at 20 aiports and a handful of venues.  Not government issued, and you do have to pay for it… draw your own conclusion.