I had the same worries that I was overreacting. My ped said DS4's vision was fine. He totally "there, there'd" me about it. But I couldn't help feeling like something wasn't right. My dear friends on this board helped me to decide to get him checked by a developmental optometrist.
And whaddya know! The DO said that there is, indeed, an issue with DS4. The glasses the DO prescribed have helped. But I suspect DS4 may need visual therapy or something more. I'm actually wondering now if he might be dyslexic--lots of backwards writing. Not just letter reversals, but writing whole words like mirror images, from R to L instead of L to R, complete with all letters reversed. And he doesn't realize it's backards. So I do think my "mommy gut" was right that something is up.
Mommy guts usually are. A check up with a DO shouldn't cost very much. If nothing else, it's worth the peace of mind to find out that you're just worrying over nothing! That's the best case scenario!