I have found the face recognition on this phone extremely reliable. But if that fails the fingerprint recognition is built in to the power button on the side and is fantastic, works every time. So many adjustments possible that I do feel this phone would be good for a visually impaired person to use. Many commands can work from the "Hey Google" facility that is built in. Yes it has finger print scanner on side of phone and facial recognition too Yes you can use without fingerprint and face recognition, also you can use the accessibility settings to make it usable for the visually impaired I hope this help all the best You can use without fingerprint or face recognition, you do not need to lock it at all if you choose not to. Yes. I don't know.####[['face recognition', 'Security#Screen Unlock', 'positive'], ['fingerprint recognition', 'Security#Screen Unlock', 'negative'], ['fingerprint recognition', 'Security#Screen Unlock', 'negative'], ['visually impaired person to use', 'Ease of Use#Audience Groups', 'positive'], ['"Hey Google" facility', 'Intelligent Assistant#Intelligent Assistant General', 'positive']]