Headaches, eyestrain and poor vision affecting a childs ability to read or see the chalkboard are just some of the school related vision problems that relate to students ability to function in the classroom. Kids change rapidly. Growth spurts cause them to change many shoe and clothes sizes and similarly eyeglass prescription changes. It's amazing how some will say they see just fine and then can't read large letters on the eyechart. Others can read letters but make frequent mistakes because of astigmatism, farsightedness or focusing problems. 

All children with performance problems in reading or general academics should have a comprehensive examination to rule out focusing or vision issues since these can make a profound difference and are sometimes the easiest to address. Improving vision also helps all the other specialists from the reading specialist to the behavior therapists.