Could I second the suggestion to take him to an eye doctor? Either an Ophthalmologist or Optometrist is fine, but a pediatric one.

Our Pediatrician told us to hold off when DS6 was 3, because "it doesn't matter until they're reading," but he ended up having major astigmatism and the Ophthalmologist we went to said that really the earlier the better because the brain is constantly developing the vision system and correcting vision will help to make sure it develops normally, at least from that point.

Don't want to scare you, but it really is important, and also don't want to contradict a Pediatrician, but I've never heard of vision self-correcting.

Both of my kiddos wear glasses and love them.