I decided to make a little interactive flash to exaggerate the concepts of the Bates method--
hope y'all like it
http://summonprettypeace.deviantart.com/art/Healthy-Eye-of-Bates-Method-91824342

Why put this in off topic? I think a good diagram would be useful for all of us...

The white halo sorrounding the black letters do not have a slow gradient like you have shown. It is thin and has a sharp gradient thus giving an embossed look to the black letters. ( as if sculpted) Even trying to imagine this is relaxing to the eye though very few of us succeed in imagining it. ( and if you can really imagine that perfectly your vision would be easily restored)