The reason why I love the underline is that it focuses our attention on where it should be. Instead of having a wide gaze and seeing the whole, it helps concentrate our eyes on the important thing.
I would say that it can be for both the young and the old, we can make it a mastery till we get used to it and are able to adjust our gaze rightly.
The underline is a very effective method, I have tried it before and yet I would recommend it to others too.
Thank you for your time...
