Pupil Distance Meter (PDM) can be called now from your app to get PD measurements. See code example below for details how to use it.
How to call from your application:
Intent intent =new Intent("com.vistechprojects.pupildistancemeter.action.MEASURE_PD");
intent.setDataAndType(IMAGE_SOURCE_URI,"image/*"); // comment this line if you don't pass image uri
startActivityForResult(intent, REQUEST_CODE); // replace REQUEST_CODE with your constant