Portia,
I've never heard of poor vision development having an impact on near-sightedness. I'm not an expert or even anything close to knowledgeable on the subject, so my lack of knowledge means nothing
However, I wouldn't spend one nanosecond worrying that your ds might have not needed glasses for eyesight had he had more or different or "better" vision therapy. My dd who needed VT had 20/20 eyesight when she was 8 years old and started VT, but by the time she was 10 had very poor near vision and now has to wear strong prescription contacts. Her eye drs and behavioral optometrists have never seen one as relating to the other, and most of the kids that I've known who have to wear glasses usually start to experience changes in eyesight acuity from 6-9 years old... whether or not they had issues that had to be addressed by vision therapy.
My guess is it's more likely genetics - are other people in your family near-sighted?
Best wishes,
polarbear
ps - the other thing I'd add - my ds, who's never had issues requiring vision therapy, also wears glasses (contacts). We wanted to put him in contacts right away when he was first given a prescription for glasses at 10 and were told by our eye dr to wait because we'd be changing out prescriptions too frequently until he was a teen and his prescription was stable - were told the same for our dd also. Both of their prescriptions stabilized around their early teens. Not sure that relates to anything at all... but it might be related to changes in eye shape as children grow. In any event, you might consider how many people you know who are near-sighted yet never had challenges requiring vision therapy.
