A CBS news affiliate in the United States aired this story about vision therapy. The main points are that school eye screenings don't check for many treatable vision problems such as visual perceptual skills or binocular vision dysfunction which make it difficult for a child to learn.
Note that people with these problems don't have a "learning disability" as that term has come to be defined to include things like dyslexia. However, vision problems make learning - 80% of which is done through our visual system - much more challenging than it is for classmates who do not have such disorders.
