The application is pretty useful and very good inintiative taken by betalabs team.I have a suggestion to give.
I think the app should be integrated with the camera app. Every time I open the app it says camera lid closed. So when I open the camera lens cover the system switches to the default camera app and says camera used by another program. So it will be good to directly integrate the app in the camera adding a new option to the toolbar, the magnifier option. It will save a quite clicks and will be helpful in those situations when a person is in a hurry and wants to magnify the text fast.