My eg/pg son (now 6) just finished 2 years of vision therapy over the holidays; he was born a VSL but born with torticollis (head tilting) and visual processing deficits. I can say it took us 6-8 months before we noticed much improvement, but then the developments started to come fast and thick.
Our behavioral optometrist told us that my son was operating a couple of grade levels above his age after examining his eyes, but it didn't really hit until the rapid developments and reading kicked in. Still, I can attest that the vision therapy takes a lot of time, patience, and effort. You've got to be diligent about doing those vision exercises, which I know can be a bugbear and rather challenging.
Being a VSL too, having a son who's VSL and been through vision therapy, I can say some of it takes time. Like Rocky mentioned, phonics doesn't always work as well with VSLs as sight words. The problem, of course, is that sight words can only take you so far unless you create your own visual method or aids. I've seen people create their own math flash cards with animals or other things in the background of numbers to assist with remembering.
Like Rocky, I excelled at spelling by visualizing it. Yes, I still do that today too.
My eg/pg son self-taught himself to read, but he didn't really master the phonics until he was comfortable reading out loud to us. Instead of browbeating about phonics, last spring/early summer (after 1 1/2 years of vision therapy) I grabbed books like Fly Guy and other easy readers to encourage him to READ, anything to get him to read. I believed that if I just got him excited and motivated about reading, I could deal with the phonics later (I'm a librarian and former teacher, by the way). Around August, after my son had easily mastered Fly Guy and started to feel more comfortable with sight words and easy readers and reading out loud to us, I went back to phonics. There's some FREE phonics lessons/materials online, which will visually help. Within a month or two, my son was pretty good with the phonics and wanted to read Magic School Bus. Well, over the holidays he's Charlie and the Chocolate Factory and now reading at a 4th grade level - quite a magical leap it seems.
