Attention Deficit Disorder (ADD) and Attention Deficit Hyperactivity Disorder (ADHD) are psychiatric disorders characterized by inattention, distractibility, hyperactivity and impulsivity. It is estimated that 30% of those with dyslexia have coexisting ADHD. Coexisting means the two conditions, ADHD and dyslexia, can occur together, but they do not cause each other. ADD and ADHD can hinder a child's academic and/or social performance. There is not an objective clinical test to confirm ADD and ADHD. Therefore, a diagnosis is based on a set of subjective symptoms. Vision problems may lead to the misdiagnosis of ADD and ADHD.
Children with vision-based learning problems can be highly distractible, have short attention spans, make careless errors, fail to complete assignments, and are often fidgety and off task. Rather than being caused by a deficit in attention, the inability to remain on task is often caused by the strain of using their eyes for long periods of time at close ranges. Two eye teaming disorders that often suggest symptoms of ADD or ADHD are convergence insufficiency and convergence excess. Children with these conditions have difficulty using both eyes together at the close up ranges required for reading and writing. After a short period of time, the print on the page begins to jump and move as they work to aim their eyes at the same point on the page, struggling with the lack of control over their eye movements. The strain forces a child to find relief, often taking the form of avoidance of the close-up tasks causing the distress. By participating in avoidance activities such as repeatedly looking around the room or out the window, talking to the peers around them or frequenting the water fountain or bathroom, a child is taking a "vision break" that he or she may not even be aware of. Children with eye teaming problems may be unaware that their vision is not working as well as it should, and therefore often do not report eyestrain or blurred or double print. As the school day progresses, a child may become increasingly fatigued and demonstrate frustration in ways reminiscent of ADD or ADHD. A child diagnosed with ADD or ADHD should have a comprehensive eye exam to determine if the diagnosis is correct or how a vision problem may be contributing to the condition.