...do you find an ordinary optomitrist screening adaquate for assuring yourself that vision is intact?
Ordinary optometrist screenings don't take tracking and convergence into account, and they don't take visual processing into account, so you can have a great report from the optometrist and still have problems getting visual information off the page without a great deal of effort.
Some signs of visual difficulties during reading include: fatigue from reading; rubbing eyes; headaches; losing place on the page; skipping parts of words or combining words that are near each other on the page when reading; using a finger or pencil to follow along on the page while rading; covering a portion of the page; a strong preference for certain head postions or light conditions while reading, moving the head or changing the position of the book frequently while reading; seeeing colors, "halos", or bands of light on the page; seeing the letters moving on the page, seeing blurred or double; squinting or blinking frequently while reading.
With some of these, oral reading is the easiest way to assess if it is an issue: skipping words, substituting words, losing place on the page, and combining words from different parts of the text are errors the reader may be completely unaware of, but which a listener who is looking at a copy of the same text can easily pick up. With many of the others, (colors, moving letters or words, halos, blurred or double vision), you would almot certainly have to ask directly if the person reading is experiencing them, because if that is the way their vision has always been, they may have no idea that everyone doesn't see things that way.
How do you assess if decoding is automatic enough?
Decoding is automatic enough to not be a drain on cognitive resources if it is automatic enough to be unconcious and reliably error-free. If the reader is aware of the act of decoding the text while reading, or has to correct mis-readings frequently, that is usually a sign that some aspect of the lower-level reading skills (either visual or phonological) is using up resources that would ideally be used instead to construct meaning.
