Here's a surprise, from the end of 
This Article about how problems in school might not be attitude or neurologically based, but rather caused by vision problems: 
And here's a big one- these kids are often misdiagnosed with attention deficit hyperactivity disorder because they can't focus more than five minutes on reading.
 I'm near-sighted and I remember the huge difference in the way I saw the world when I first got glasses.  My vision's pretty bad but even at that it wasn't found out until a sight and hearing test we were given in 5th or 6th grade.  It's not hard to imagine that a more-subtle vision impairment, like this kid's blurred vision, could cause problems without being detected as such.  And in a climate where ADHD is the fashionable diagnosis to make...   
Of course, not *all*, or even I think a great percentage, of ADHD cases can be vision related in truth, but even if it's a small percentage it means we're drugging kids unnecessarily, and that's a bad thing.  That's really what irks me about the whole ADHD thing is that it's over- and mis-diagnosed, and it seems that the main solution (even when paired with other, behavior-oriented treatments) is to prescribe medication.  And I think that's a Bad Thing, with capital letters.