What Jon's doctor is describing is a completely different method of vision improvement.
Using this method, the subject is forced to wear special hard contact lenses whose purpose is to 'flatten' the cornea. After wearing them for a few days, the cornea gets slightly flattened, but the cornea can only be deformed a little bit, so the maximum improvement this method can give is about -1.5D, just like Jon's doctor said. The worst part is that as soon as you take off the hard contacts, the cornea starts to go back to normal, and in a few days, the effect disappears. This method is not addressing the problem (i.e. the extrinsic eye muscles). It is simply trying to fix the symptoms, by changing the cornea, much like surgery changes the cornea, without the risks or permanent effect of surgery. This method will not improve the eye's ability to 'point' at what it sees, it will not improve the saccadic movements or depth perception, and it will not improve corrected acuity (i.e. vision with contacts or glasses on). And, since it only gives such a minor, temporary improvement, it isn't useful for most of us. In fact, you don't even need these special hard contact lenses to experience this effect. All you need to do is press the butt of your palms against your closed eyes (while looking straight ahead), for about 30 minutes per day. Sure enough your cornea will flatten, and your vision might improve slightly, until you stop the exercise. I don't recommend doing this because pressing against your eyes might not be good. This exercise should not be confused with a relaxation exercise called 'palming' where the palms do not press against the eyes.
For those still skeptical about the possibility of poor vision being corrected naturally, I recommend contacting someone who has actually experienced enormous improvement. The fastest & greatest improvement that has been accurately recorded is the case of Janet Goodrich, who took a 2-month NVI course and improved from 20/800 (about -8) to 20/60 (about -0.75). She was so amazed that she wrote a book and began teaching NVI. You can find her book on amazon and you might be able to contact her through the publisher. Skeptics, of course, will just say that she's a liar, and her NVI instructor who recorded her improvement, and all the other student witnesses could also be liars!
You might also want to chat with people on the net who have experienced dramatic improvements (you can find them on newsgroups and e-mail lists). One unfortunate point is that most of the people who have experienced complete and permanent improvement no longer frequent the lists (why bother at that point), but some good-hearted people, who have fixed their vision, remain on the groups or e-mail lists to help others along.
Eric Fattah
BC, Canada