NTT Docomo's latest phone will be using multimodal biometrics, page-9

In a nutshell BF, the Wavefront technology does not deliver a 'perfect' match, rather it knows the range within which your tear film will reside. Every time you blink it changes slightly but stays within your calculated range. This is how you have what they term the one billion individual PINs. In this way, anyone with a photo or some sort of replica of your eye will not be able to trick the system because what they have would be an EXACT match every time and that raises the red flag for this technology because you should never be able to get an exact match to a previous reading.