The idea is to stand up really straight with good posture while smiling trying to cultivate as much spiritual joy as possible. He uses visualisations such as flying in the air absorbing lightening and imagining yourself in a state of perfect joy and health while importantly having perfect eyesight. Then you mentally tell your body to conform to this mental ideal. It is important to remove all doubt about whether it is possible to change your eyesight and instead believe fully that you will.
I have been trying this for the last week and I visualise myself running and dancing around in a forest at one with nature, picking fruits like the garden of eden. Now I'm curious if this approach is similar to the Bhakti yoga described in the book and can Bhakti yoga be used to heal. Or do ideas like this exist in yoga at all?
The reason I ask is that I am a bit worried desires of this sort are selfish and might be a hindrance to future work but I would also like to improve my eyesight which is weak.