Brian X. Chen, reviewing the new flagship phone from Samsung for The New York Times:
That brings us to what stinks about the Note 8. Some of the
biometrics, including the ability to unlock your phone by scanning
your face or irises, are so poorly executed that they feel like
marketing gimmicks as opposed to actual security features.
The iris scanner shines infrared light in your eyes to identify
you and unlock the phone. That sounds futuristic, but when you set
up the feature, it is laden with disclaimers from Samsung. The
caveats include: Iris scanning might not work well if you are
wearing glasses or contact lenses; it might not work in direct
sunlight; it might not work if there is dirt on the sensor.
I don’t wear glasses or contact lenses and could only get the iris
scanner to scan my eyes properly one out of five times I tried it.
Shipping features like this is what separates Apple from Samsung.