Visual learning plays a vital role in class. It has been estimated as 87% of our learning is visual (6% hearing and 7% rest of body) (American Academy of Optometry).
In reading we need to see the letters, recognise the order and remember that visual signal to access our language centre. A poor visual reader has to decide each letter sound blend (phoneme) and link them together. Word by word readers do just this.
If your brain is spending so much time analysing or keeping eye muscles working together it has no time to process, recall or comprehend. These problems can discourage you from prolonged reading.
I do not diagnose dyslexia or dyscalculia, this needs to be undertaken by a specialist teacher or educational psychologist. I do identify and treat the visual aspects of a learning issue. I can use lenses, colour or vision training to develop a more efficient system.