A couple of thing strike me about your post. One is that yes, six year old kids write letters and numbers backwards and mix up similar ones. Second is that I believe it is a "developmental optometrist" with the title you're looking for to diagnose visual tracking and other vision issues related to reading. You might try one of those colored filters to see if that just 'fixes it' before spending the money. Third is that whether due to dyslexia or or not, it is a bad habit to guess at the word. Kids should decode when learning to read and establishing their reading habits. Eide & Eide have more to say about different strategies depending on the child's relative strengths. Fourth is that many with dyslexia hate to write because it utilizes all their weaknesses. Six year olds are often weak in the same areas due to their age, making it difficult to know what to do.
It's so hard to know what to do when your kids has so many strengths to compensate for something that might be hindering them academically. Your son is lucky that you're on top of it!
