A major problem with biometric authentication is that, when it doesn’t work, there are few good options to proceed with the authentication. When the system says that’s not your eyeball, there’s no fallback akin to “Forgot your password?” You have to revert to some less discerning authentication method, such as a PIN.
Some vendors are trying to deal with this by using a simultaneous, multi-biometric method. “Simultaneous” is important because using two methods consecutively would take more time, resulting in end users’ resistance and lower participation rates.
One vendor, Sensory, is making serious headway in figuring out interesting ways to use dual biometrics.