I don't have any advice other than it could be dyslexia and definitely seek out the optometrist again. It could be a focusing problem or astygmatism or something else!
When writing, he's recently started writing letters and numbers backward, specifically, lower case "e", the typical "p, b, g, q, d", and "5", "2", "3", "6", "9", "7". He usually puts the tails on "j" and "g" backward. Sometimes when sounding out a word, he'll say the sounds in order, but then he'll write the corresponding letters in reverse order. Usually the beginning and ending letter are correct, but the middle sounds are sometimes reversed. He HATES to write! We use a white board a lot, and this helps. He prefers this to pencil and paper.
This was my DS, though he didn't write fine and then start to write backwards; he started writing backwards. It IS common for children to write these letters (and numbers) backwards. And it is common for them to read a word correctly and write it jumbled. But those also can be a sign of eye issues or dyslexia as well.
I will say that DS now, with practicing so much at school and at home (he likes to write, but he HAS to write on the right surface - i.e., dotted line paper - or it's trouble!), he rarely writes his letters and numbers backwards AND he recognizes that they are, if he does. So encourage him to keep trying!
Good luck!
