Why does Face ID work after cataract surgery?

Will Tingle asked Nikita Thomas from Anglia Ruskin University...

Nikita - Biometrics are essentially measurements of biological features, and facial recognition technology uses biometrics to measure certain facial landmarks that generate a unique identifier, or sometimes it's called a face print, of your own face. The landmarks measured with this type of technology include features related to your nose, your ears, your chin, and so on. But the landmarks related to the eyes are the distance between the eyes and the depth of the eye sockets. These are measured by the software detecting where your upper and lower eyelids are and where the corners of your eyes are. Intraocular lens implants replace the lens in your eye, and that is actually located inside of the eye, so it's behind the pupil and behind the iris, which is the coloured part of the eye. As the facial recognition technology only looks at the eyelids and the corners of the eye, which are structures outside of the eye itself, it's unlikely that the intraocular lens implants that are inside of the eye would affect the detection of these outside structures. However, it is the case that during the surgery your eyelids are held open with an instrument called a lid speculum. It is possible that the surgery itself and the holding of these eyelids may have slightly altered the positions or the elasticity of your eyelids post-surgery so that the facial recognition software may not detect your eyelids in the exact same precise location as they were pre-surgery.

Will - So is there anything that can be done to fix this issue?

Nikita - In this situation, it would probably be best to attempt to redo the facial ID profile for both your phone and the banking app. But if the problem persists even after doing this, then it points to more of a problem with the facial recognition software itself. This is especially true if the facial recognition software is working on your phone, but not on the app as technically they should both be reading the same unique profile.