Binocular Instability refers to the ability to use both eyes together (more along the lines of depth perception)
Occulomotor tracking is the ability to move the eyes across the page smoothly as in reading. This may be why your child skips the small words, he may be missing them because of insufficient tracking.
Convergence Insufficiency is the abilit to move the eyes from far away to near, like attempting to copy from a blackboard (at a distance) to the paper on your desk.
Yes it can be related to dyslexia and several other diagnoses. Most likely, what narrows his diagnosis is his ability to read and comprehend and yet have the underlying visual motor/perceptual issues.
My dd7 has been in therapy for 5 months now and we are working on many of the same issues. Are you working with a school to help deal with these issues? We are having a terrible time getting the teachers to accept this diagnosis and make accomodations accordingly.
Good Luck!!
