Use a finger scanner which only allows you to use them and if the fingerprint doesn't match the thieve gets a electric shock.
A Global Positioning System tracker should be added to your mobile phones. This will allow you to track down your mobile device in case it does get stolen and the authorities can't help you.
Never let your phone be more than 1 meter away from you at one time. If you are blind keep it on some sort of chain that stays on your person at all times.