The Samsung Galaxy S5, the successor of Galaxy S4, is expected to feature an eye-scanning sensor that will unlock the phone by scanning eyes. But this is just a rumor, and there is nothing official about it.
The sources also report a possible launch in Feb 2014. What really will be the specs of the new Galaxy are still unknown. Let’s wait and watch till then. By the time, you can have a look at the Android 4.3 that is just released for the S4.