If the disparity is great enough, the brain can't combine the two pictures. The result is double vision. At the close up distances required for reading, children with eye teaming problems are only able to aim their eyes together correctly for short periods of time. As their ability to accurately aim their eyes breaks down, their eyes end up pointing at slightly different places on the page. The result is a great deal of visual strain and eventually blurred, scrambled, or double print.
Vision is clear, single, and comfortable as long as both eyes are aiming at the same point.
Children with eye teaming problems find it difficult to maintain the inward eye aim required for reading. As the eyes tire, they float apart and end up pointing at different places on the page. The result is blurred or double print. Of course, reading and comprehension become increasingly difficult as the child strains to aim both eyes at the same place to keep the print from blurring, jumping, or splitting apart . In addition, children with eye teaming problems can be highly distractible, finding it difficult to concentrate and remain on task when the strain on their eyes is so great.