No. Unfortunately there is no homeopathic, natural or other method to change the refractive error of one's eyes besides spectacle / contact lens correction and refractive surgery. Anyone who tells you differently is trying to sell you something. It would be a great and revolutionary discovery, but it simply is not possible.
Hard question. I don't think there is a "proven" way to "increase" one's vision. I have heard and read about methods that their investors claim to work to improve vision without use of eyewear, but I can tell you that if there was one according to them, it would just be so rigorous that it's almost next to impossible to follow it.