Once again, Bates can not change the shape of the eyeball, the lens or the cornea.
What it can do is to train (if you don't like the word 'exercise') the muscles that control the shape of the lens.
Whether 'they' said the world was or wasn't flat, or whether or not one has an 'open mind' (whatever that means !) is irrelevant. You may derive some benefit from the Bates technique, and if it works for you then congratulations. But it is not magic, and the effects, I suspect, are not permanent without continuous repetition.
As with anything else, in order to avoid disappointment you have to separate wishful thinking from common sense.