Sometimes people go ages needing glasses before they get tested for them even as adults. My eyes changed a lot when I was 13 (to do with puberty, this is a common time for eyesight to change) and I went ages not knowing that I really needed to have my prescription changed. Getting a lot of headaches was the only real indicator that something was up and even then I didn't say anything because it wasn't in my nature to. But my schoolwork really went downhill. A few letters home from teachers made my mum really mad at me and that is when I told her about my headaches.
So I got tested and it was found that I was going short-sighted in my right eye (before that both my eyes had been +) so that my left eye was +2.00 and my right was -2.00. That is quite a big difference and I don't know how I was getting along like that without noticing but it was probably because my left eye was/is weak so even though it had the clearer vision for distances, I just wasn't using it enough.
But a new prescription made such a difference. I could see leaves on trees and the mortar between bricks on buildings again, heh. It was (and is) a pleasure to see clearly.
Bodaccea, the point I guess I am trying to make is to not blame yourself for your urchin's vision problems. It is hard enough to get an adult to recognise they have vision problems let alone a little kid who doesn't know any difference. I had glasses at your urchin's age as well. Younger, actually, because I had had operations so the doctors were anticipating vision problems. I can't remember being tested for glasses at that age but I imagine it wasn't easy for them to get the correct prescription but they did. I had to see an ophthalmologist a lot and I do remember that.
Your urchin's vision will be corrected at a young age and that is definitely a good thing. He is long-sighted too so the problem is not very noticeable to those who experience it (far vision is clear, up close is harder to focus). Astigmatism is also pretty easy to live with in most cases as well (I have it in both eyes but can only tell I have it in my right eye when I read without glasses on).
Here is a line picture test for astigmatism where you can tell pretty easily if you have it (at least I can) because some of the lines appear clear and the rest are fuzzy: