Just a quick update. I made an appt for DS7 to see the eye doctor next week, but in the meanwhile I got him the large print version of HP4. They're off school today, so I asked him to try just sitting down and reading it, and to tell me if/when he gets a headache. 27 minutes later (he had timed it on his watch), he told me he needed to stop for a food break, but no headache. He told me he was really excited that now he would be able to finally finish the rest of the HP books, and asked me if there are other large print books he might like.
So, not sure whether it's his vision or tracking, but it's good to know that there's something to help keep his reading enjoyment up until we can resolve the issue.
