Where to start: Bates newby

[Anke]

Hi all,
I've just started to read "Better eyesight without glasses" and am a bit confused as to what's the best approach to get started for me. 
I have been crosseyed since I was 2, with the eyes going to the outside. I had one operation (muscle cut) when I was 7 on both eyes, and another one on the left eye only (it had started to go to the outside again) when I was 25. My left eye is nearsighted, the right one farsighted. Up to last year I wore glasses only for driving and just used my eyes alternately. Then my right eye got more farsighted (I'm 40 now and can read books etc only when I hold them at arm's length when I look with my right eye), and my left eye started to roll to the inside for a change when I look into the distance (distance being anything more than armslength away from me).
The optometrist gave me prism glasses, which were a relief at first, but they don't feel quite right and I would rather improve my eyesight. Where do I start? Is it best to try and improve each eye on its own first, or focus on getting them to team up? I'm lucky and see double only when I'm really really tired and have a full field of vision.
Your help is much appreciated!
Thank you, Anke