As I just posted in another thread, I have reduced my nearsighted vision to half, from about -1.50/-1.25 to -0.75/-0.50.
Look for
natural vision
or
vision improvement
on Google.
But let me write the basics:
The focus of the eye is more or less static, unchangeable, but the lens you focus with is not. It is controlled by (I think) 6 muscles in each eye.
If you are nearsighted, you cannot relax these muscles enough to focus far (as if you cannot reach your feet with your hands, legs stretched out).
If you are farsighted, you cannot contract these muscles far enough.
If you are hindsighted ...
Anyway, for nearsightedness, the solution is (stretching) exercises, wearing reading glasses when reading or doing other near work (or weaker glasses if you are heavily nearsighted). Reading glasses are some places sold as "computer glasses", but they are essentially the same.
Becoming nearsighted has been suggested is the result of prolonged exposure to very short focsing, as if reading at a too close distance. Wearing reading glasses resembles focusing at a distance further away, forcing your eye muscles to relax. I remember reading about a Japanese study, where Japanese people were compared with regard to their need for vision correction. There was a clear tendency of the higher educated group to be more nearsighted, while those mainly having a background with shorter education were much less prone to being nearsighted.
I don't know whether it is all true, but it worked for me. Now I am just too lazy to keep up the work to entirely get rid of my nearsightedness.
This is not new at all. The Bates method is over 50 years old I think. This article is from 1973:
http://www.chinamyopia.org/Preventionmagazine1973.htm but it has a lot of useful information in it.
This page contains more recent information. I cannot find the Japanese study I mention above, but there are plenty of other studies cited here
http://www.preventmyopia.org/validation.html - pointing Myopia/nearsightedness to reading/TV/computer work.
Edit: Here is an animation (Flash) explaining how Myopia can be prevented for kids
http://www.preventmyopia.org/flashanimation.html. There is also some effect when you are older, but the earlier you start, the better.